placebo: [13] Placebo started life as the first person future singular of the Latin verb placēre ‘please’ (source of English please), and hence meant originally ‘I will please’. It was the first word of the antiphon to the first psalm in the Roman Catholic service for the dead, Placēbo Dominō in rēgiōne vivōrum ‘I will please the Lord in the land of the living’. The word’s medical use emerged at the end of the 18th, and arose from the notion of a medicine ‘pleasing’ the patient rather than having any direct physiological effect. => please[placebo etymology, placebo origin, 英语词源]