(verb) : pĭo, āvi, ātum, 1, pius.
* To seek to appease, to appease, propitiate by sacrifice (syn. place).
* Lit.: Silvanum lacte piabant,Hor. Ep. 2, 1, 143: ossa,Verg. A. 6, 379: busta (i.e. Manes),Ov. M. 13, 515: Janus Agonali luce piandus erit,id. F. 1, 318.
* Transf.
* To honor with religious rites, to celebrate: ubi piem Pietatem,Plaut. As. 3, 1, 3: aras ture,Prop. 3, 10 (4, 9), 19: in magicis astra piare focis,to perform sacred rites,id. 1, 1, 20.
* To purify with sacred rites (syn.: procuro, lustro): si quid tibi piandum fuisset,Cic. Dom. 51.
* To make or seek to make good, to atone for, expiate: damna,Ov. A. A. 3, 160: mors morte pianda est,id. M. 8, 483: fulmen,to avert by sacrifice the misfortune portended by lightning,id. F. 3, 291: nefas triste,to atone for, avert the penalty,Verg. A. 2, 184; Ov. H. 19, 194: cometes terrificum sidus, ac non leviter piatum,Plin. 2, 25, 23, § 92.
* To punish, avenge: culpam morte,Verg. A. 2, 140: grande nefas et morte piandum,Juv. 13, 54.
* To free from madness, Fest. p. 213 Müll.: jube te piari de meā pecuniā: nam ego quidem insanum te esse certo scio,Plaut. Men. 2, 2, 17; so id. ib. 3, 2, 51.

s. TLL