The word twilight comes from a compound of two Old English words, "twi" meaning two, and "light." However it doesn't mean two kinds of light or light occurring twice. Rather, it's a different interpretation. The Online Etymology Dictionary states, "Exact connotation of twi- in this word is unclear, but it appears to refer to 'half' light... Compare also Sanskrit samdhya 'twilight,' literally 'a holding together, junction,' [and] Middle High German zwischerliecht, literally 'tweenlight.'" Both of these -- the idea of holding together or of being between two things -- is an ideal description for this in-between time of morning and evening when the sun isn't in the sky but its light still brightens things enough for us to see, even if only just barely. The diffused light adds a purple and pink tinge to everything, making it a magical and very temporary moment at the beginning and end of each day.