Placebo \Pla*ce"bo\, n. [L., I shall please, fut. of placere to please.]

1. (R. C. Ch.) The first antiphon of the vespers for the dead.

2. (Med.) A prescription intended to humor or satisfy.

To sing placebo, to agree with one in his opinion; to be complaisant to. --Chaucer.

Source: Webster's Revised Unabridged Dictionary (1913)