-or. [L. -or: cf. OF. -or, -ur, -our, F. -eur.]
1.
A noun suffix denoting an act; a state or quality; as in error, fervor, pallor, candor, etc.
2.
A noun suffix denoting an agent or doer; as in auditor, one who hears; donor, one who gives; obligor, elevator. It is correlative to -ee. In general -or is appended to words of Latin, and -er to those of English, origin. See -er.
© Webster 1913.