The names of bodies, disease and the ways people tried to understand them.
placebo (n.)
A placebo can be an inactive preparation given in a medical study. The word once belonged to a prayer.1
In Latin, placebo means I shall please. It began a verse sung in the evening service for the dead, and the service came to be called by that first word.12
In medieval English, to sing placebo could mean to flatter someone. By the eighteenth century, physicians used the word for something given to please a patient rather than for a specific therapeutic action.12
Placebos later became important in controlled studies, where they help researchers distinguish the effects of a treatment from effects associated with receiving care and expecting improvement. A word from the service for the dead became part of the language of testing medicine.1
Half the volunteers received a placebo.