1 variant: 夜 yè

1 midnight

2 in the middle of the night

1 nightclub

1 nighttime

2 evening or night (e.g. classes)

1 New Year's Eve family dinner

1 lit. to make night as day (idiom); fig. to burn the midnight oil

2 work especially hard

1 to make day as night (idiom, from Book of Songs); fig. to prolong one's pleasure regardless of the hour

1 to work from morning to night (idiom)

1 to rise early and sleep late (idiom); to work hard

2 to study diligently

3 to burn the candle at both ends

1 to stay out all night (idiom)