Etymology 1

Noun

1. A ship of burden, or war with a round, bulky hull.
   • 1485, Sir Thomas Malory, Le Morte Darthur, Book V:

     As the Kynge was in his cog and lay in his caban, he felle in a slumberyng [...].

Etymology 2

Noun

1. A tooth on a gear
2. A gear; a cogwheel
3. A unimportant individual in a greater system.
   • 1976, Norman Denny (English translation), Victor Hugo (original French), Les Misérables

     ‘There are twenty-five of us, but they don’t reckon I’m worth anything. I’m just a cog in the machine.’

   • 1988, David Mamet, Speed-the-Plow

     Your boss tells you “take initiative,” you best guess right—and you do, then you get no credit. Day-in, ... smiling, smiling, just a cog.

4. a projection or tenon at the end of a beam designed to fit into a matching opening of another piece of wood to form a joint

Verb

1. to cheat at dice
2. to cheat; to play or gamble fraudulently