Entries linking to crusader
"military expedition under the banner of the cross," 1706, a respelling or replacement of croisade (1570s), from French croisade (16c.), Spanish cruzada, both from Medieval Latin cruciata, past participle of cruciare "to mark with a cross," from Latin crux (genitive crucis) "cross" (see crux).
The modern English form is comparatively late, and even the earlier croisade is post-Middle English (French croisade replaced earlier croisée). Middle English nouns were croiserie (c. 1300), creiserie.
Especially in reference to the medieval expeditions undertaken by European Christians for recovery of the Holy Land from Muslims. Generally they are counted as seven between 1095 and 1271, but some smaller efforts (e.g. the "Children's Crusade") are omitted and the word sometimes is extended to other religiously motivated expeditions (e.g. against the Albigenses or the Prussians). Figurative sense of "vigorous campaign for a moral cause or against a public evil" is from 1786.
English agent noun ending, corresponding to Latin -or. In native words it represents Old English -ere (Old Northumbrian also -are) "man who has to do with," from Proto-Germanic *-ari (cognates: German -er, Swedish -are, Danish -ere), from Proto-Germanic *-arjoz. Some believe this root is identical with, and perhaps a borrowing of, Latin -arius (see -ary).
Generally used with native Germanic words. In words of Latin origin, verbs derived from past participle stems of Latin ones (including most verbs in -ate) usually take the Latin ending -or, as do Latin verbs that passed through French (such as governor); but there are many exceptions (eraser, laborer, promoter, deserter; sailor, bachelor), some of which were conformed from Latin to English in late Middle English.
The use of -or and -ee in legal language (such as lessor/lessee) to distinguish actors and recipients of action has given the -or ending a tinge of professionalism, and this makes it useful in doubling words that have a professional and a non-professional sense (such as advisor/adviser, conductor/conducter, incubator/incubater, elevator/elevater).