English Dictionary

o'clock

/əˈklɒk/

adv

(modifying a numeral, one to twelve) In conjunction with a numeral, indicates the time within a twelve-hour period (midnight to noon or noon to midnight), specifically the time when the hour hand of a clock points precisely to the symbol or marking corresponding to the designated numeral.

I always wake up at six o'clock in the morning.

意味（1）

(modifying a numeral, one to twelve) In conjunction with a numeral, indicates the time within a twelve-hour period (midnight to noon or noon to midnight), specifically the time when the hour hand of a clock points precisely to the symbol or marking corresponding to the designated numeral.

We are expected to be there at six o'clock in the morning!

意味（2）

(humorous) In conjunction with a term representing an action or event that occurs daily, indicates the time that said action or event occurs, or first occurs.

That same evening at tea-time — (I am sorry to have to introduce you to another eating-scene, but the hours in English households are usually marked by repasts. It is a daily calendar of feasts — breakfast o’clock, dinner o’clock, &c., […] ).

意味（3）

(with a numeral, one to twelve) In conjunction with a numeral, indicates the direction, relative to the speaker or a vehicle, especially an aircraft, corresponding to the direction the hour hand is pointing at the time corresponding to the numeral, with twelve representing directly ahead and three being to the right.

It's at nine o'clock about two feet in from the edge of the branch. You need to know your o'clocks (nondigital) to spot birds.