From Latin plācātus, past participle of plācō (“appease, placate”, literally “smooth, smoothen”), from Proto-Indo-European *plāk- (“smooth, flat”), from Proto-Indo-European *pele- (“broad, flat, plain”). Related to Latin placeō (“appease”), Old English flōh (“flat stone, chip”). More at please.
- (transitive) To calm; to bring peace to; to influence someone who was furious to the point that he or she becomes content or at least no longer irate.
- (to calm): enrage
Derived terms 
- second-person plural present tense of placare
- second-person plural imperative of placare
- feminine plural past participle of placare
- second-person plural present active imperative of plācō