A tooth on a gear.

A gear; especially a toothed wheel in machinery.

A minor, replaceable person within a large organization.

A projecting tenon made to fit a mortise.

A rough pillar left to support a mine roof.

To fit with a cog or cogs.

Of a motor, to snap to preferred positions when unpowered.

Initialism: center of gravity.

Abbreviation: course over ground.