noun
antique clock; old clock
Refers to an old-fashioned or antique clock, often with a nostalgic or quaint feel. Commonly used for pendulum clocks or vintage timepieces.
祖母の家には大きな古時計がある。
There is a large antique clock at my grandmother's house.
この古時計はもう動かない。
This old clock doesn't work anymore.
骨董品 is a broader term for antiques or curios, whereas 古時計 is limited to clocks.
Compound of 古 (ふる, 'old') and 時計 (とけい, 'clock'). The reading ふるどけい shows rendaku (sequential voicing) on the second element.