Designate
mid 17th century (as an adjective): from Latin designatus ‘designated’, past participle of designare, based on signum ‘a mark’.
wiktionary
Borrowed from Latin designatus, past participle of designare. Doublet of design.
etymonline
designate (adj.)
early 15c., "marked out, indicated" (a sense now obsolete), from Latin designatus, past participle of designare "mark out, devise, choose, designate, appoint," from de "out" (see de-) + signare "to mark," from signum "identifying mark, sign" (see sign (n.)). Meaning "appointed or nominated but not yet installed" is from 1640s.
designate (v.)
1791, "appoint or select for a particular purpose," from designate (adj.) or else a back-formation from designation, or formed from Latin designatus. Meaning "to mark out or indicate" is from 1801; that of "distinguish from others by a name, give a name to" is by 1818. Related: Designated; designating.
