Chain-of-thought
Also: CoT, chain-of-thought prompting, chain of thought
A prompting technique (and a trained behavior in reasoning models) where the model generates step-by-step reasoning, via an instruction such as "Let's think step by step" or worked examples. Spending tokens on intermediate steps markedly improves math, logic and multi-step questions.
Example
"If 5 machines make 5 widgets in 5 minutes, how long do 100 machines take for 100 widgets? Let's think step by step." Reasoning that each machine makes one widget in 5 minutes leads to the correct 5 minutes instead of the intuitive 100.