Placebo
Etymology
From Latin placebo, "I shall please," the future tense of placere, "to please." The word first appeared in medieval funeral prayers ("placebo Domino"), and for centuries it labeled a flatterer — someone who only tells you what pleases you. Medicine borrowed it in the 1700s for a remedy given more to satisfy the patient than to cure, and modern trials made it the baseline every real drug must beat.
noun · /pluh-SEE-boh/
An inactive treatment — a sugar pill or sham procedure — that can still produce real improvement because the patient expects it to help.
What it names
A reminder that expectation itself is a physical force: believing you are being cared for can measurably change how you feel.
Example
In the study, a third of people given a placebo reported that their headaches eased anyway.
Related idea
Nocebo is the mirror image — when negative expectation produces real harm rather than relief.