Two o'clock — a time expression indicating 2:00 (AM or PM determined by context). Used as a noun for the time and adverbially to mean 'at two o'clock'.
会議は午後2時に始まります。
The meeting will start at 2:00 PM.
私は毎日2時に薬を飲むことにしている。
I take medicine every day at 2:00.
今、もう二時だ。遅刻しそうだ。
It's already two o'clock now. I'm going to be late.