The Gloaming

evening 

from O.E. æfnung "evening, sunset," verbal noun from æfnian "become evening, grow toward evening," from æfen "evening" (see eve). As a synonym of even (n.), it dates from mid-15c. and now entirely replaces the older word in this sense. Another O.E. noun for "evening" was cwildtid.

1. (n.) evening
the latter part of the day and early part of the night.

2.  evening
the period from sunset to bedtime.

What time do you think evening ends? Try and figure it out, you'll be surprised.

twilight 

late 14c. (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 English with reference to evening twilight but occasionally used of morning twilight (a sense first attested mid-15c.). Figurative extension is first recorded c.1600

Nautical Twilight, Nautical Dawn, The Gloaming, The Magic Hour, Twilight -  These are all names we give to the phenomenon of light with no sun in the sky.  Once the sun disappears from the horizon, there is a lovely time when the day dwindles.  Look tonight and see the violet light illuminating the greens and flowers around you.  The sun's last rays are bending and weakening.

Look to the melancholy blueness of morning's return, too.  The world begins to get light, lighter, lighter until finally, dawn. 

In filmmaking, these times are known as "The Magic Hour" because light is so beautiful, cameras pick up amazing images that can't be reproduced with human technology (yet).