SG Heritage Dictionary

Crepusculous [\N] Webster's Dictionary 1828

CREPUSCULAR, CREPUSCULOUS adjective Pertaining to twilight; glimmering; noting the imperfect light of the morning and evening; hence, imperfectly clear or luminous.

Crepusculous [Adjective] Webster's Dictionary 1913

1. Pertaining to twilight; glimmering; hence, imperfectly clear or luminous.

2. Flying in the twilight or evening, or before sunrise; -- said certain birds and insects.