crepuscular

from WordNet (r) 3.0 (2006)

crepuscular
    adj 1: like twilight; dim; "the evening's crepuscular charm"

from The Collaborative International Dictionary of English v.0.48

Crepuscular \Cre*pus"cu*lar\ (-k?-l?r), Crepusculous
\Cre*pus"cu*lous\ (-l?s), a. [Cf. F. cr['e]pusculaire.]
   1. Pertaining to twilight; glimmering; hence, imperfectly
      clear or luminous.
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            This semihistorical and crepuscular period. --Sir G.
                                                  C. Lewis.
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   2. (Zool.) Flying in the twilight or evening, or before
      sunrise; -- said certain birds and insects.
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            Others feed only in the twilight, as bats and owls,
            and are called crepuscular.           --Whewell.
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