- a small Eurasian brown bat, Eptesicus serotinus.
- Also: serotinal (sɪˈrɒtɪnəl), serotinous biology produced, flowering, or developing late in the season
- either of two insectivorous bats, Eptesicus serotinus or Vespertilio serotinus: family Vespertilionidae
adj.“late,” 1590s, from French sérotine, from Latin serotinus “that which comes late; that which happens in the evening,” from sero, adverb of serus “late” (see soiree). Also as a noun, a type of small, brown bat, from 1771. Related: serotinous, in botany (1880) “appearing later in the season than usual.”