Definitions
Glossary
Short, plain-English answers to the terms behind AI engineering, PHP and software architecture, each with an example and a link to the in-depth guide.
No terms match. Try a shorter word.
A
- Agentic AIAgentic AI describes AI systems that act with a degree of autonomy: they plan multi-step work, use tools and other software, and adjust based on results, instead of…AI Engineering
- AI agentAn AI agent is software that uses a large language model to pursue a goal on its own: it decides which steps to take, calls tools such as APIs, search or code, looks at…AI Engineering
- AI hallucinationAn AI hallucination is a confident but false or unsupported output from a generative AI model, such as an invented fact, quote, statistic, API method or citation. It…AI Engineering
B
C
- CDPCustomer data platformA CDP (customer data platform) is software that collects customer data from every channel, including website, apps, CRM, e-commerce and support, and merges it into one…Digital Transformation
- Context windowA context window is the maximum amount of text, measured in tokens, that a large language model can take into account at once: the system prompt, conversation history,…AI Engineering
D
E
- EmbeddingsEmbeddings are lists of numbers (vectors) that represent the meaning of a piece of text, an image or another item, produced by an embedding model. Items with similar…AI Engineering
- Event-driven architectureEvent-driven architecture (EDA) is a design style in which services communicate by publishing events, records that something happened such as “OrderPlaced”, and other…Software Architecture
F
G
H
I
J
K
L
- LLMLarge language modelAn LLM (large language model) is an AI model trained on very large amounts of text to predict the next token in a sequence. That simple objective, at scale, lets it…AI Engineering
- LLM tokensTokens are the small pieces of text a large language model reads and writes: whole words, parts of words, punctuation or spaces. In English one token averages about…AI Engineering
M
- MCPModel Context ProtocolMCP (Model Context Protocol) is an open standard for connecting AI applications to tools and data. An MCP server describes its tools, resources and prompts in one…AI Engineering
- MicroservicesMicroservices are an architecture style where an application is built as a set of small, independently deployable services, each owning one business capability and its…Software Architecture
N
O
P
- Prompt injectionPrompt injection is an attack on AI applications where text written by an attacker, typed in by a user or hidden in a web page, email or document the AI reads, contains…Security & Resilience
- PSRPHP Standards RecommendationA PSR (PHP Standards Recommendation) is a specification published by the PHP Framework Interop Group (PHP-FIG) so that PHP libraries and frameworks can work together.…PHP & Backend
Q
R
S
- Semantic versioningSemVerSemantic versioning (SemVer) is a version-numbering scheme in the form MAJOR.MINOR.PATCH, where each number signals the kind of change: MAJOR for incompatible changes,…PHP & Backend
- Strangler fig patternThe strangler fig pattern is a way to replace a legacy system gradually: you put a routing layer in front of it, build new functionality piece by piece in a modern…Software Architecture
T
- Technical debtTechnical debt is the future cost of shortcuts and outdated decisions in software: code, architecture or infrastructure that works today but makes every later change…Engineering Leadership
- Tool callingFunction callingTool calling, also called function calling, lets a large language model ask your application to run a function. You describe the available tools with names and JSON…AI Engineering