/kɒg; kɑˇ/

1 each of a series of teeth on the edge of a wheel, that fit between those of a similar wheel, so that each wheel can cause the other one to move （齿轮的）轮牙; 轮齿. =>illus 见插图.
2 (idm 习语) a cog in the ma`chine (infml 口) person who plays a necessary but small part in a large organization or process 不重要的但不可少的人.

n[C]
[Date: 1200-1300; Origin: From a Scandinavian language]
a wheel with small bits sticking out around the edge that fit together with the bits of another wheel as they turn around in a machine
one of the small bits that stick out on a cog
a cog in the machine/wheel
someone who only has a small unimportant job in a large business or organization