四更

sìgēng
fourth of the five night watch periods 01:00-03:00 (old)

CEDICT

old

Entry Composition

1 四 sì
  1. four
  2. 4
2 更 gēng
  1. to change or replace
  2. to experience
  3. one of the five two-hour periods into which the night was formerly divided
  4. watch (e.g. of a sentry or guard)