a. One of a series of teeth or similar projections on the circumference of a wheel, or the side of a bar, etc., which, by engaging with corresponding projections on another wheel, etc., transmit or receive motion.Cogs are either separate wooden pieces attached by mortices and the like, or are cut out of the substance of the wheel, or cast in one with it. The name was probably first given to the wooden pins inserted sideways into the rim of a wheel, which caught the rungs or trundles of a lantern-wheel; hence cog and round, a mechanical arrangement of this type. hunting cog: in cogged wheels which have a certain proportion to each other, an extra cog given to the larger, by which there is secured a continuous change of cogs engaging with each other and consequently equal wear.

†b. A float-board. Perhaps only a mistake.

c. to slip a cog: to make a single unsuspected mistake in one's work or calculations.

d. figurative. One who holds a necessary but usually insignificant position in a large organization or group. Frequently a cog in a or the (..) machine, etc.

b. a cog-wheel.

a. The act of cogging at dice; a particular method or way of doing this. [In quot. a1592, taken by some to mean ‘false dice for cogging’; but it is coupled with ‘devices’ and ‘shifts’.]

b. An act of cogging or cheating.Apparently an isolated use.

a. intransitive (Dicing.) To practise certain tricks in throwing dice.From contextual evidence it would seem that ‘cogging’ generally designated some sleight of hand, made use of to control the falling of a die; occasionally it may mean the substitution of a false die for the true one. The notion that it meant ‘to load the dice’ appears to be a mistake of modern dictionaries, which has, however, strongly influenced the use of the word by modern novelists, etc.; cf. esp. cogged adj.² The following quotations show the change of explanation in the dictionaries:

1699 B. E. New Dict. Canting Crew Cog, to cheat at Dice; Cog a Die, to conceal or secure a Die.

1730 N. Bailey et al. Dictionarium Britannicum To Cog,..to cheat at dice-play.

1755 S. Johnson Dict. Eng. Lang. To cog a die, to secure it, so as to direct its fall; to falsify. So 1847 in Craig.

1847–78 J. O. Halliwell Dict. Archaic & Provinc. Words Cog, to load a die: so some later Dicts.

b. transferred. To cheat at cards.

a. transitive. to cog a die or the dice: fraudulently to control or direct their fall.

b. With complement: to cog forth, to cog in (a die).

a. intransitive. To employ fraud or deceit, to cheat.

b. transitive. To cheat, deceive.

a. To employ feigned flattery; to fawn, wheedle.

†b. transitive. To wheedle (a person) out of or into a thing, or (a thing) from a person. Obsolete.

a. gen. To produce or put forth cunningly and fraudulently. Obsolete.

†b. To foist in, into; to palm off fraudulently on, upon; to put out or utter falsely. Obsolete.