"make clear or manifest, throw light upon, explain, render intelligible," 1560s, perhaps via Middle French élucider (15c.) or directly from Late Latin elucidatus, past participle of elucidare "make light or clear," from assimilated form of ex "out, away" (see ex-) + lucidus "light, bright, clear," figuratively "perspicuous, lucid, clear," from lucere "to shine," from PIE root *leuk- "to shine, be bright." Related: Elucidated; elucidates; elucidating.