An archaic or variant spelling of crusade, particularly from early English sources.
From Old French 'croisade,' which comes from 'crois' (cross). The Latin root 'crux' (cross) is the ultimate origin, as crusaders wore the cross as their symbol.
The 'crois-' family of words all relate to the cross symbol—crusade, croisade, croisée—and watching how these words evolved shows how a single symbol (the cross) spawned entire linguistic families across European languages.
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