noun, adverb
Refers to the time 2:00, either AM or PM depending on context.
会議は２時から始まります。
The meeting starts at two o'clock.
今、２時です。
It's two o'clock now.
Means 'two hours' (duration), not a point in time.
Compound of 二 (に, 'two') and 時 (じ, 'o'clock').