late 15c., "financial loss incurred through damage to goods in transit," from French avarie "damage to ship," and Italian avaria; a word from 12c. Mediterranean maritime trade (cf. Spanish averia; other Germanic forms, Dutch avarij, German haferei, etc., also are from Romanic languages), of uncertain origin. Sometimes traced to Arabic 'arwariya "damaged merchandise," but this might as easily be a borrowing of the word from the Franks. Meaning shifted to "equal sharing of such loss by the interested parties." Transferred sense of "statement of a medial estimate" is first recorded 1735. The mathematical extension is from 1755.