锁眼

锁眼	suǒ yǎn	keyhole
锁	suǒ	to lock; to lock up / a lock (CL:把)
锁	suǒ	old variant of 锁
眼	yǎn	eye (CL:只,双) / (often used with 一) a look; a glance / small hole / (bound form) salient point / classifier for wells, cave-dwellings etc