时钟 (shízhōng) is a noun meaning "clock." It refers to a timepiece, particularly a wall clock or large clock, and can also be used metaphorically, as in 末日时钟 (Doomsday Clock), a symbolic indicator of global threats.
墙上的时钟显示现在是三点整。
Qiáng shàng de shízhōng xiǎnshì xiànzài shì sān diǎn zhěng.
The clock on the wall shows it's exactly three o'clock.
这个时钟走得有点慢,每天差两分钟。
Zhège shízhōng zǒu de yǒudiǎn màn, měi tiān chà liǎng fēnzhōng.
This clock runs a bit slow, losing two minutes every day.
教室里的时钟坏了,需要换电池。
Jiàoshì lǐ de shízhōng huài le, xūyào huàn diànchí.
The clock in the classroom is broken and needs new batteries.