Where does “activator” come from?

Activator comes from English active, derived from Latin activus, from Latin agere meaning to do or drive, ultimately from Proto-Indo-European h₂eǵ-.

activator (English): One who, or that which, activates; Something that...

Definitions

activator traces back through 3 separate lines of ancestry.

Step	Language	Word	Meaning
1	English	activate	To encourage development or induce increased...
2	English	active	Having the power or quality of acting; causing...
3	Middle English	actyf	active, reactive
4	Old French	actif	active
5	Latin	āctīvus	active
6	Ancient Greek	ἐνεργητικός	Able to act on; acting on; Active; In the active...
7	Ancient Greek	ἐνεργέω	to be in action or activity, to operate; to...
8	Ancient Greek	ἐνεργός	at work, active
9	Ancient Greek	ἐν-	in, within; on
10	Ancient Greek	ἐν	in, on, at; among; in, at, or during the time of
11	Ancient Greek	δέρμα	skin, hide
12	Ancient Greek	γλυφή	carving, carved work; hole cut
13	Ancient Greek	-ῐ́ᾱ	{{l\|en\|-ia}}; "suffix forming abstract feminine...
14	Proto-Indo-European	-íh₂	—
15	Proto-Indo-European	-h₂	Creates collective nouns, which refer to groups...

Step	Language	Word	Meaning
1	English	‐or	Creates an agent noun, often from a verb, indicating a person or object (often machines or parts of them) that do the verb or part of speech with which they are formed
2	Middle English	-our	—
3	Old French	-eor	Alternative form of -or
4	Latin	-ator	-ator, -er; second-person singular future passive...
5	Latin	-tor	-er
6	Proto-Italic	-tōr	Forms agent nouns to verb stems
7	Proto-Indo-European	-tōr	Derives agent nouns from verbs, denoting someone...
8	Proto-Indo-European	-tor-s	—

Step	Language	Word	Meaning
1	Romanian	activa	to activate; to activate, to enable; definite...
2	French	activer	to activate; to speed up; to stoke
3	French	-er	Forms infinitives of first-conjugation verbs
4	Middle French	-er	Forms infinitives of first-conjugation verbs;...
5	Old French	-ier	suffix used to form infinitives of first...