Do you know ghouls from goblins and ghosts?
1560s, noun of action from elucidate.
1560s, perhaps via Middle French élucider (15c.) or directly from Late Latin elucidatus, past participle of elucidare "make clear," from ex- "out, away" (see ex-) + lucidus "clear" (see lucid). Related: Elucidated; elucidates; elucidating.