Research · TechCrunch ·

Your AI Glossary: Hallucinations, Tokens, and the Words That Matter

A practical guide to essential AI terminology—what hallucinations actually are, why tokens matter for costs, and what terms like 'agentic' and 'RAG' mean for working with models.

Based on reporting by TechCrunch — analysis by dalili

AI conversations are drowning in jargon. Terms like 'hallucination,' 'token,' 'agentic,' and 'RAG' get thrown around in articles and product announcements, but many readers are left nodding along without clarity on what these actually mean for practical use.

A hallucination, in AI terms, isn't random—it's a model confidently asserting false information because it pattern-matched to training data that suggests a plausible-sounding answer. Understanding this distinction matters: hallucinations aren't bugs to be fixed so much as fundamental constraints of how LLMs work.

Tokens are the atomic unit that models actually process. Understanding token counts matters directly to your wallet—API costs scale with token use, not word count. A sentence might be 5 words but 8 tokens depending on punctuation and word boundaries.

Agentic systems are models given the ability to take actions—call APIs, update databases, make decisions—based on natural language instructions. RAG (Retrieval-Augmented Generation) is a technique for giving models access to external knowledge bases without retraining. Both are increasingly central to how companies deploy LLMs.

Key takeaways

  • Hallucinations are fundamental to how LLMs work, not bugs
  • Tokens are the atomic unit that determines API costs
  • Agentic systems and RAG are reshaping how companies deploy models

Why it matters

Clear terminology is the foundation for working effectively with AI. Understanding what hallucinations and tokens actually are changes how you evaluate models and costs.

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