midnight

noun

1. the middle of the night; twelve o’clock at night.

adjective

2. of or relating to midnight.
3. resembling midnight, as in darkness.

Idioms

4. burn the midnight oil, to study or work far into the night: After months of burning the midnight oil, he really needed a vacation.

noun

1. 1. the middle of the night; 12 o’clock at night
   2. (as modifier)the midnight hour
2. burn the midnight oil to work or study late into the night

n.Old English mid-niht, or middre niht (with dative). See mid + night. Midnight oil symbolizing “late night work” is attested from 1630s.