1387 (implied in
twilighting), a compound of
twi- +
light (n.) Cognate with Du.
tweelicht (16c.), Ger.
zwielicht. Exact connotation of
twi- in this word is unclear, but it appears to refer to "half" light, rather than the fact that twilight occurs twice a day. Cf. also Skt.
samdhya "twilight," lit. "a holding together, junction," M.H.G.
zwischerliecht, lit. "tweenlight." Originally and most commonly in Eng. with ref. to evening twilight but occasionally used of morning twilight (a sense first attested c.1440). Figurative extension is first recorded 1600.
[twahy-lahyt] 
