köken: Etymology tree Latin tremō Proto-Indo-European *-os Proto-Indo-European *-s Proto-Indo-European *-ōs Proto-Italic *-ōs Latin -or Latin tremor From tremō + -or.
köken: From Old Irish crith, from Proto-Celtic *kritos (“trembling, fever”). Probably not related to croith (“to shake”), which generally refers to an intentional act.