piaculum

From Latin piāculum. Doublet of piacle.

piaculum (plural piacula)

1. An expiatory sacrifice.
2. The victim in such a sacrifice.
3. An act requiring expiation.

• piacular

From piō (“to appease, purify, expiate”) +‎ -culum (instrumental suffix). Given Umbrian pihaclu (abl. sg.), Proto-Italic *pwīāklom can be reconstructed.

• (Classical Latin) IPA^(key): [piˈaː.kʊ.ɫũː]
• (modern Italianate Ecclesiastical) IPA^(key): [piˈaː.ku.lum]

piāculum n (genitive piāculī); second declension

1. propitiatory sacrifice, expiation, atonement

   Synonym: lūstrum

2. an animal offered up in sacrifice, a victim
3. sin, crime, guilt

Second-declension noun (neuter).

• “piaculum”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “piaculum”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• piaculum in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.