Glossary of AI & Machine Learning

266 plain definitions for the terms that come up when you are actually building and shipping AI systems.

A45 terms

Abductive Logic Programming

A framework in AI/ML for solving problems declaratively using abductive reasoning, allowing for incompletely defined...

Abductive Reasoning

In AI/ML, abductive reasoning is inferring the most likely explanation from incomplete or ambiguous data.

Abstract Data Type (ADT)

A mathematical model defining a data type by its behavior, operations, and values from a user's perspective.

Abstraction

Simplifying complex systems by focusing on essential features, ignoring irrelevant details in AI/ML contexts.

Accelerating Change

In AI/ML, it refers to the rapid advancement of technology, leading to faster, more impactful innovations.

Action Language

A formalism in AI for modeling state transitions resulting from actions within dynamic systems.

Action Model Learning

Learning how actions affect an environment, informing software agents' decision-making in AI/ML.

Action Selection

Deciding the next action for intelligent systems based on current state, goals, and available actions.

Activation Function

Determines a neural network node's output based on its input, influencing the network's ability to learn complex patterns.

Active Learning

A strategy where the model identifies uncertain data points for labeling to optimize the annotation process.

Adaptive Algorithm

Dynamically adjusts its strategy during runtime based on feedback to optimize performance in AI/ML tasks.

Adaptive Neuro-Fuzzy Inference System (ANFIS)

Integrates neural networks and fuzzy logic to approximate nonlinear functions with learning capabilities.

Admissible Heuristic

A heuristic that never overestimates the cost to reach a goal in pathfinding and search algorithms.

Adversarial Examples

Inputs to machine learning models intentionally designed to cause the model to make a mistake.

Affective Computing

Computing that recognizes, interprets, and simulates human emotions using interdisciplinary approaches.

Agent Architecture

Design framework for intelligent agents, outlining component arrangement for decision-making and behavior execution.

AI Accelerator

Hardware designed to speed up AI tasks, particularly in neural networks, machine vision, and machine learning.

AI-complete

Problems as complex as achieving general human-level intelligence, unsolvable by simple algorithms.

Algorithm

A step-by-step procedure for calculations, data processing, and automated reasoning in computing and AI/ML.

Algorithmic Efficiency

Measures an algorithm's resource usage, including time and space, crucial for optimizing AI/ML performance.

Algorithmic Probability

A method from algorithmic information theory for assigning prior probabilities to observations, developed by Ray Solomonoff.

AlphaGo

AI program by Google DeepMind that plays Go, first to beat a professional human player on a full-sized board.

Ambient Intelligence

Electronic environments that are sensitive and responsive to the presence of people.

Analysis of Algorithms

The study of algorithm performance in terms of time and space complexity.

Analytics

The discovery, interpretation, and communication of meaningful patterns in data.

Annotation

The process of adding metadata to a dataset, essential for training AI/ML models.

Annotation as a Service (AaaS)

Outsourcing the data labeling process to specialized service providers, leveraging their expertise and resources.

Annotation Bias

Systematic errors introduced during the labeling process, affecting the fairness and performance of models.

Annotation Efficiency

Measures and techniques to maximize the output of the annotation process with minimal input, crucial for scaling AI...

Annotation Guidelines

A set of rules and standards for how data should be labeled, ensuring consistency and accuracy across annotators.

Annotation Project Management

The oversight of the entire annotation workflow, from task allocation to progress tracking to quality control.

Annotation Scalability

The ability to efficiently expand the data labeling process to accommodate growing datasets, a critical aspect for evolving AI...

Annotation Workflows

The sequence of steps and processes involved in annotating data, from initial setup to final review and approvals.

Answer Set Programming

A declarative programming approach for solving NP-hard search problems using stable model semantics.

Anytime Algorithm

An algorithm that can provide a valid solution even if interrupted before completion.

Application Programming Interface (API)

A set of protocols and tools for building and integrating application software.

Approximate String Matching

Finding strings that closely match a pattern, rather than exactly.

Approximation Error

The difference between an exact value and its approximation.

Argumentation Framework

A structure for dealing with and reasoning about conflicting information.

Artificial General Intelligence (AGI)

AI with human-like cognitive abilities across a wide range of domains and tasks.

Artificial Immune System

Algorithms inspired by the human immune system's mechanisms for adaptive learning and memory.

Artificial Intelligence (AI)

Machine-based systems that emulate human cognitive functions such as learning, problem-solving, and decision-making.

Artificial Intelligence Markup Language (AIML)

An XML dialect for developing natural language conversational agents.

Artificial Neural Network (ANN)

Computing systems inspired by the biological neural networks that constitute animal brains.

Association for the Advancement of Artificial Intelligence (AAAI)

A society promoting research, education, and responsible use of artificial intelligence.

B15 terms

Backpropagation

A method for updating neural network weights by propagating errors backward from output to input.

Backpropagation Through Time (BPTT)

An extension of backpropagation for training recurrent neural networks on sequence data.

Backward Chaining

An inference method that starts from the goal and works backward to deduce the required facts.

Bag-of-Words Model

A text representation model that disregards order and grammar, focusing on word frequency.

Bag-of-Words Model in Computer Vision

Treating image features as "words" for classification, using vectors of feature occurrence counts.

Batch Normalization

A method to normalize neural network inputs, improving stability and performance by adjusting and scaling activations.

Bayesian Programming

Specifying and solving problems using probabilistic models under conditions of uncertainty.

Bees Algorithm

An optimization algorithm inspired by the foraging behavior of honey bees.

Behavior Informatics

The study and analysis of behaviors through informatics to derive insights and intelligence.

Behavior Tree

A hierarchical model for structuring decision-making and task execution in AI, robotics, and game development.

Belief-Desire-Intention (BDI) Software Model

A model for programming intelligent agents based on their beliefs, desires, and intentions.

BERT (Bidirectional Encoder Representations from Transformers)

A technique for natural language processing pre-training, demonstrating the importance of contextual word meanings.

Bias

Systematic errors in data or models that can lead to unfair outcomes.

Bias Mitigation

Strategies and techniques to reduce or eliminate bias in data and models, ensuring fairness and equity in AI applications.

Bias-Variance Tradeoff

A fundamental tradeoff in machine learning between model simplicity (bias) and responsiveness to data (variance).

C14 terms

Catastrophic Forgetting

The tendency of an artificial neural network to completely and abruptly forget previously learned information upon learning new information.

Capsule Network

A type of neural network design that attempts to better model hierarchical relationships in data than standard CNNs.

Central Processing Unit (CPU)

The primary component of a computer that performs most of the processing inside the computer.

Chatbot

A software application used to conduct an on-line chat conversation via text or text-to-speech.

Classification

A supervised learning task that maps an input to a specific category or label.

Cluster Analysis

The task of grouping a set of objects in such a way that objects in the same group are more similar to each other.

Cognitive Computing

The use of computerized models to simulate the human thought process in complex situations.

Collaborative Filtering

A method used by recommender systems to make predictions about the interests of a user by collecting preferences from many users.

Computer Vision

A field of AI that enables computers to derive meaningful information from digital images, videos and other visual inputs.

Conditional Random Field (CRF)

A class of statistical modeling methods often applied in pattern recognition and machine learning for structured prediction.

Convolutional Neural Network (CNN)

A deep learning algorithm which can take in an input image and assign importance to various aspects/objects in the image.

Cost Function

A mathematical formula used to measure how well a machine learning model is performing.

Cross-Validation

A technique used for assessing how the results of a statistical analysis will generalize to an independent data set.

CUDA

A parallel computing platform and application programming interface model created by Nvidia.

D12 terms

Data Augmentation

A technique used to increase the amount of data by adding slightly modified copies of already existing data.

Data Mining

The process of discovering patterns in large data sets involving methods at the intersection of machine learning, statistics, and database systems.

Data Science

An interdisciplinary field that uses scientific methods, processes, algorithms and systems to extract knowledge and insights from data.

Dataset

A collection of related sets of information that is composed of separate elements but can be manipulated as a unit by a computer.

Decision Tree

A flowchart-like structure in which each internal node represents a test on an attribute, each branch represents the outcome of the test.

Deep Learning

Part of a broader family of machine learning methods based on artificial neural networks with representation learning.

Deep Reinforcement Learning

A subfield of machine learning that combines reinforcement learning and deep learning.

Dimensionality Reduction

The transformation of data from a high-dimensional space into a low-dimensional space so that the low-dimensional representation retains some meaningful properties.

Discriminator

The part of a Generative Adversarial Network (GAN) that attempts to distinguish between real data and data produced by the generator.

Distributed Computing

A field of computer science that studies systems whose components are located on different networked computers.

Dropout

A regularization technique for reducing overfitting in neural networks by preventing complex co-adaptations on training data.

Dynamic Programming

Both a mathematical optimization method and a computer programming method.

F12 terms

F1 Score

A measure of a test's accuracy, defined as the harmonic mean of precision and recall.

Face Recognition

A technology capable of identifying or verifying a person from a digital image or a video frame from a video source.

Factor Analysis

A statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved variables called factors.

False Negative

An error in binary classification in which a test result incorrectly indicates the absence of a condition when it is actually present.

False Positive

An error in binary classification in which a test result incorrectly indicates the presence of a condition when it is actually absent.

Feature Engineering

The process of using domain knowledge to extract features (characteristics, properties, attributes) from raw data via data mining techniques.

Feature Extraction

In machine learning, pattern recognition and image processing, it starts from an initial set of measured data and builds derived values (features) intended to be informative and non-redundant.

Feedforward Neural Network

An artificial neural network where connections between the nodes do not form a cycle.

Few-shot Learning

A type of machine learning problems where the model is trained with only a few examples for each class.

Fine-tuning

The process of taking a pre-trained model and adapting it to a new, but related, task by training it further on a smaller dataset.

Forward Pass

The initial step in the training of a neural network where the input data is passed through the network to generate an output.

Fuzzy Logic

A form of many-valued logic in which the truth values of variables may be any real number between 0 and 1.

M14 terms

Machine Learning

A field of inquiry devoted to understanding and building methods that 'learn' – that is, methods that leverage data to improve performance on some set of tasks.

Machine Translation

A subfield of computational linguistics that investigates the use of software to translate text or speech from one language to another.

Markov Chain

A stochastic model describing a sequence of possible events in which the probability of each event depends only on the state attained in the previous event.

Markov Decision Process (MDP)

Provides a mathematical framework for modeling decision-making in situations where outcomes are partly random and partly under the control of a decision maker.

Matrix

A rectangular array or table of numbers, symbols, or expressions, arranged in rows and columns.

Mean Absolute Error (MAE)

A measure of errors between paired observations expressing the same phenomenon.

Mean Squared Error (MSE)

Measures the average of the squares of the errors—that is, the average squared difference between the estimated values and the actual value.

Metaprogramming

A programming technique in which computer programs have the ability to treat other programs as their data.

Minimax

A decision rule used in artificial intelligence, decision theory, game theory, statistics, and philosophy for minimizing the possible loss for a worst case (maximum loss) scenario.

Mixture Model

A probabilistic model for representing the presence of subpopulations within an overall population, without requiring that an observed data set should identify the sub-population to which an individual observation belongs.

Model

A mathematical representation of a real-world process, often used in machine learning to make predictions.

Monte Carlo Method

A broad class of computational algorithms that rely on repeated random sampling to obtain numerical results.

Multi-agent System

A computerized system composed of multiple interacting intelligent agents.

Multilayer Perceptron (MLP)

A class of feedforward artificial neural network (ANN).

R12 terms

R-squared

A statistical measure that represents the proportion of the variance for a dependent variable that's explained by an independent variable or variables in a regression model.

Random Forest

An ensemble learning method for classification, regression and other tasks that operates by constructing a multitude of decision trees at training time.

Recall

The fraction of the total amount of relevant instances that were actually retrieved.

Recurrent Neural Network (RNN)

A class of artificial neural networks where connections between nodes form a directed graph along a temporal sequence.

Regression

A set of statistical processes for estimating the relationships between a dependent variable and one or more independent variables.

Regularization

The process of adding information in order to solve an ill-posed problem or to prevent overfitting.

Reinforcement Learning

An area of machine learning concerned with how intelligent agents ought to take actions in an environment in order to maximize the notion of cumulative reward.

ReLU (Rectified Linear Unit)

An activation function defined as the positive part of its argument: f(x) = max(0, x).

Residual Network (ResNet)

A specific type of artificial neural network that uses skip connections, or shortcuts, to jump over some layers.

Robotic Process Automation (RPA)

A form of business process automation technology based on metaphorical software robots or on artificial intelligence / digital workers.

Robotics

An interdisciplinary branch of computer science and engineering that involves the design, construction, operation, and use of robots.

Robustness

The ability of a system to resist or overcome adverse conditions.

T19 terms

Technological Singularity

Hypothetical future point where technological growth becomes uncontrollable, leading to transformative changes to civilization.

Temporal Difference Learning

Reinforcement learning methods that update value estimates based on the difference between subsequent predictions.

Tensor Network Theory

Mathematical framework modeling the transformation of sensory data into motor responses by neuronal networks using tensors.

TensorFlow

Open-source library for numerical computation and large-scale machine learning, using data flow graphs.

Theoretical Computer Science

Branch of computer science that deals with the mathematical aspects of computing and computational theory.

Theory of Computation

Branch of computer science studying the limits and capabilities of computing machines and algorithms.

Thompson Sampling

Probabilistic method for balancing exploration and exploitation in multi-armed bandit problems by sampling from belief...

Time Complexity

Measure of the amount of computational time an algorithm takes to complete as a function of input size.

Tokenization

Breaking down text into smaller units (tokens) for analysis in NLP, crucial for data preprocessing.

Transfer Annotation

Reusing existing dataset annotations in new, but similar, contexts to minimize additional labeling work.

Transfer Learning

Adapting a pre-trained model for a new, but related, task to reduce the need for extensive new data.

Transformer

Deep learning model using self-attention to process sequential data, significant in natural language processing and beyond.

Transhumanism

Movement advocating for enhancing human capabilities through advanced technologies.

Transition System

Conceptual model describing discrete systems' states and transitions, used in computational theory.

Tree Traversal

Process of visiting each node in a tree data structure in a specific order, exactly once.

True Quantified Boolean Formula (TQBF)

A formal language of fully quantified Boolean formulas where every variable is bound and the formula is true.

Turing Machine

Abstract computational model capable of simulating any algorithm via tape manipulation based on predefined rules.

Turing Test

Test assessing a machine's ability to exhibit human-like intelligence in conversations, devised by Alan Turing.

Type System

Framework within programming languages for assigning types to program constructs, enhancing reliability and performance.

A - Z Directory

266 terms, from Abductive Logic Programming to Zero-shot Learning.

Knowing the word is the easy part. We build the systems these terms describe, run them on your data, and hand them over to your team.

FAQ

Questions people ask

What is this glossary for?

Plain definitions for the terms that come up when building production AI systems — 101 entries covering machine learning, agents, evaluation and reinforcement learning. Each one is written to be understood without the surrounding jargon.

Who is it written for?

Engineers and technical leads who keep meeting a term in papers or vendor decks and want a straight answer rather than a paragraph of hedging.

How are the definitions written?

One sentence that answers what it is, then context on where it actually matters. If a term is contested we say so rather than picking a side silently.

Can I link to a single term?

Yes. Every entry has its own page and its own URL, so you can link a specific definition in a doc or a code comment.

Can we quote these definitions?

Yes, with attribution to ReinforcedX and a link to the term page. They are written to be quotable.

How often is it updated?

Terms are added as they become load-bearing in real work. We remove entries that turned out to be vendor coinage rather than concepts.

Is there a term missing?

Probably. Tell us which one and, if it is genuinely used in production work, it gets added.

Do you explain how these apply in practice?

The glossary defines; the AI systems guides show the concepts working together in a real architecture. The two are meant to be read alongside each other.

Is this aimed at beginners?

It assumes general software literacy but no ML background. If you can read an API doc you can read these.

Can we get help applying any of this?

Yes — that is the day job. Book a working session and we will map the concepts onto your actual system.

Copyright © 2026
ReinforcedX, Inc.
All rights reserved