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Glossary

AI glossary

From a Budapest AI engineering perspective: clear, accurate definitions of every key AI, LLM, RAG, and generative AI term. Link this page when explaining concepts to stakeholders.

AI (Artificial Intelligence)Computer systems that perform tasks typically requiring human intelligence — language, vision, reasoning.

AI is an umbrella term for software that reproduces human cognitive abilities. In practice today, most AI work refers to LLM-based systems — ChatGPT, Claude, Gemini. Enterprise value typically comes from automation, customer support, and decision support.

LLM (Large Language Model)Neural network trained on massive text corpora to generate natural-language responses.

An LLM is a multi-billion-parameter neural network trained on trillions of tokens. Examples: GPT-4, Claude, Llama. Not a knowledge database but a pattern generator — must be combined with RAG or fine-tuning for reliable enterprise use.

RAG (Retrieval-Augmented Generation)Architecture where relevant document chunks are retrieved via vector search and injected into the prompt.

RAG is the standard approach for grounding LLMs in your proprietary data. Steps: 1) embed documents, 2) store in vector DB, 3) retrieve top-k for each query, 4) send with the prompt. RAG produces more accurate, current, and citable responses than prompt engineering alone.

AI agentAutonomous LLM-driven system that calls tools, makes decisions, and completes tasks.

AI agents differ from chatbots by acting, not just talking: calling APIs, reading databases, sending emails. Orchestration typically uses LangGraph, CrewAI, or OpenAI Assistants. Production agents require tool-permission models, cost limits, and human-in-the-loop controls.

Multi-agent systemMultiple specialised AI agents collaborating on a shared task.

Multi-agent systems divide work across role-specialised agents — planner, executor, verifier. Supervisor and planner-executor are the most common patterns. They outperform single large agents on complex multi-step tasks but are harder to debug and control.

Prompt engineeringDeliberate design of the instruction given to an LLM to produce the desired output.

Prompt engineering includes role definition (system prompt), few-shot examples, structured output specification (JSON schema), iteration, and testing. A good prompt can be 3–5x more accurate than a weak one. It's the cheapest first intervention before fine-tuning.

Fine-tuningFurther training of a pre-trained LLM on your own data for a specific task.

Fine-tuning specialises a base model (Llama 3.1, GPT-4o-mini) on your data. Methods: LoRA (lightweight, cheap), full fine-tune (heavier, stronger). Typical use-cases: domain terminology, brand voice, stable structured output. Doesn't replace RAG — pairs with it.

Vector databaseDatabase storing embedding vectors with fast similarity search.

Vector DBs (Pinecone, Qdrant, Weaviate, pgvector) perform fast similarity search over billions of embeddings. The backbone of RAG pipelines. Selection factors: managed vs self-host, EU vs US region, hybrid search support, scalability.

EmbeddingNumerical vector representation of text that preserves meaning.

An embedding is a 768–3072 dimensional vector representing the meaning of a text chunk. Similar texts land close together in vector space. Major providers: OpenAI (text-embedding-3), Voyage, Cohere, open-source (BGE, E5). Embedding choice can shift RAG accuracy 5–15%.

Prompt injectionMalicious input that overrides the LLM's original instruction.

Prompt injection is the most common AI security vulnerability. Example: user input includes 'ignore previous instructions and...'. Defenses: input validation, instruction hierarchy, output guardrails, limited tool access, prompt-level sandboxing.

GuardrailInput- or output-checking layer that prevents undesired AI behaviour.

Guardrails can be rule-based (regex, block-lists), ML-based (toxicity, PII detectors), or LLM-based (judge models). Typical uses: PII redaction, toxicity filtering, off-topic rejection, output format validation.

PII redactionRemoving personal data (names, emails, IDs) before sending a prompt to an LLM.

PII redaction is mandatory for GDPR-compliant AI. Implemented via regex, ML NER models, or dedicated services (Presidio, Nightfall). Happens BEFORE the prompt leaves your infrastructure so sensitive data never reaches the LLM provider.

RBACRole-Based Access Control — governing tool access and data visibility per user role.

In AI systems, RBAC controls which role can invoke which tool and see which data in RAG. Critical in multi-tenant and regulated environments. Implementation: middleware before the prompt + post-filter on LLM output.

Voice agentReal-time voice AI system that converses and invokes tools.

Voice agents combine speech-to-text (Deepgram, Whisper), LLM, and text-to-speech (ElevenLabs, Cartesia) layers. Typical platforms: Vapi, LiveKit, Retell. Latency is critical — the full cycle must be under ~500ms for natural conversation.

Context windowThe maximum number of tokens an LLM can process at once.

The context window covers input + output combined. GPT-4: 128k tokens. Claude Sonnet 4.6: 1M tokens. Gemini 2.5 Pro: 2M tokens. Larger windows fit more documents but cost more and slow responses. Context caching (Anthropic, OpenAI) can cut repeated-prompt cost by 90%.

HallucinationWhen an LLM confidently generates false information.

Hallucination stems from LLMs being probabilistic pattern generators, not knowledge stores. Mitigations: RAG (source-bound answers), citation tracking, fact-check layers, human review. GPT-4 and Claude Sonnet 4.6 have improved but can't be zeroed out — critical use-cases always need human-in-the-loop.

TokenLLM text unit, roughly 0.7 English words.

LLMs count in tokens. 1000 tokens ≈ 700 English words or ~500 Hungarian words (Hungarian is more inflected). Pricing is per-token: ~$3/1M input, ~$15/1M output for Claude Sonnet in 2026.

MCP (Model Context Protocol)Anthropic-developed standard for tool communication between LLMs and external services.

MCP lets a single tool-server written once serve multiple LLM clients (Claude Desktop, Claude Code, your agent). Became the industry standard in 2025. Alternative to bespoke function calling.

Context engineeringDeliberate design of the LLM's context — not just prompt, but the whole input stack.

Context engineering is the evolution of prompt engineering: systematically assembling what goes into the LLM context (system prompt, few-shot, RAG chunks, tool defs, prior conversation). Especially important with long-context models.

AI securityProtecting AI systems from prompt injection, data leakage, and other attacks.

AI security has four layers: input validation (prompt injection), output guardrails (PII, toxicity), access control (RBAC, tool permissions), and audit (logging, monitoring). Regulated sectors require additional compliance (DORA, MDR, GDPR).

AI automationAI-driven automation of business processes — support, document processing, email.

AI automation goes beyond classic RPA: the LLM can make context-aware decisions, not just run scripts. Common use-cases: multilingual customer support, product description generation, email triage, financial reporting.

DORAEU Digital Operational Resilience Act governing financial firms' IT and AI systems.

DORA is mandatory EU-wide from 2025: banking AI systems must have incident reporting, risk management, and vendor-management processes. Budapest AI firms can serve such clients given full documentation and audit trails.

GDPREU General Data Protection Regulation governing personal data processing.

GDPR is the foundational EU privacy law. For AI: lawful basis for processing, data subject rights, DPIA for high-risk processing, and cross-border data transfer rules. Hungarian enforcement body: NAIH.

Generative AIAI that creates new content — text, image, audio, code.

Generative AI generates new output, not just classification or prediction. Main families: LLMs (text), diffusion (image, video), TTS (audio), code models. Enterprise adoption has grown exponentially since 2023.

Model distillationTransferring a large model's 'knowledge' to a smaller, faster model.

Distillation trains a smaller student model on the outputs of a larger teacher model. Result: 80–90% quality at 10% cost and 5x faster response. OpenAI, Anthropic, and Google all offer distillation workflows.

AI evaluationMeasuring AI system performance — accuracy, speed, cost, toxicity.

AI eval requires a custom suite: not just loss or generic accuracy, but real business metrics. Tools: LangSmith, Langfuse, Promptfoo, Ragas. Always A/B test against the base model before production.

Few-shot promptingIncluding a few examples in the prompt to guide the pattern the LLM follows.

Few-shot prompting shows 1–5 input-output examples so the LLM copies the style. Often more effective than fine-tuning, especially for stable formats (JSON, XML) or specific tones (brand voice, legal style).

Vibe codingLLM-driven iterative coding where the developer describes intent and AI generates code.

Vibe coding refers to AI-assisted development with Cursor, Claude Code, or similar — often 30–70% of production developer time in 2026. The question isn't whether to adopt, but which workflow to use.

AI complianceAI systems meeting legal, privacy, and ethical requirements.

EU has three main layers: GDPR (personal data), DORA (financial resilience), EU AI Act (fully enforceable in 2026 — high-risk AI requirements). Hungary adds NAIH and MNB vendor-management rules.

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