a combination of -ate 1 and -or 2 that forms nouns corresponding to verbs ending in -ate 1 ,denoting a human agent ( agitator; mediator; adjudicator ) or nonhuman entity, esp. a machine ( incubator; regulator; vibrator ) performing the function named by the verb. Cf. -tor, -or 2 .
[ -ator, orig. not a suffix, but the termination of nouns formed with -tor -TOR from verbs whose stems ended in -a-; in English, Latin loanwords ending in -ator have been reanalyzed as derivatives of the past participles in -tus (see -ATE 1 ) and a suffix -or (see -OR 2 ), and many new English nouns derived from English verbs based on Latin past participles (e.g., VIBRATOR from VIBRATE) ]