12 foundational concepts that separate fluent AI practitioners from people who are guessing. The vocabulary you need to move fast in an AI-native world.
12 Core Concepts
TERM 01
01 · Core Architecture
LLM
Large Language Model
The AI brain behind ChatGPT, Claude, Gemini, Copilot.
Trained on billions of documents.
Predicts the most likely next word — at scale.
TERM 02
02 · Failure Mode
HALLUCINATION
Confident Wrong Output
When AI makes stuff up.
Confidently. Completely wrong.
Happens when training data has gaps.
TERM 03
03 · Unit of Compute
TOKEN
Chunk of a Word
The building block of AI communication.
Not a word — a chunk of a word.
More tokens = more cost in enterprise settings.
TERM 04
04 · Two Phases
TRAINING VS INFERENCE
Teaching vs. Doing the Work
Training = teaching the model.
Inference = the model doing the work.
You can't have the second without the first.
TERM 05
05 · Specialization
FINE TUNING
Specialized Training
Taking a general model.
Feeding it specialized data.
Making it smarter at one specific thing.
TERM 06
06 · Learning Loop
REINFORCEMENT
Reinforcement Learning
AI learns by trial, reward, and repeat.
Like training a dog — but the dog is a neural network.
This is how reasoning models get sharper.
TERM 07
07 · Compression
DISTILLATION
Large → Small Model
Teaching a small model to mimic a large one.
Faster. Cheaper. Nearly as good.
Likely how GPT-4 Turbo was built.
TERM 08
08 · Architecture Pattern
RAG
Retrieval-Augmented Generation
AI + your own documents.
Retrieves relevant context before responding.
Reduces hallucinations dramatically.
TERM 09
09 · Reasoning Mode
CHAIN OF THOUGHT
Step-by-Step Reasoning
Breaking a complex problem into steps.
Like showing your work in math class.
Slower — but far more accurate.
TERM 10
10 · Model Parameter
WEIGHTS
Learned Intelligence as Math
Numbers that shape what the model "knows."
Start random. Adjust during training.
The model's actual learned intelligence — stored as math.
TERM 11
11 · Training Signal
VALIDATION LOSS
Training Progress Score
A score that tells you how well training is going.