夜中

Noun

 * 1)  midnight

Etymology 1
Compound of.

Noun

 * 1) late at night, the middle of the night
 * 2) midnight

Usage notes
The sense of specifically at 12:00 AM is more commonly expressed by the term.

Etymology 2
Apparently from.

Noun

 * 1) nighttime, the night, the period of time during the night

Etymology 3
Compound of.

Noun

 * 1) the entire night, the period of time throughout the night