The difference between Butt cheek and Cheek

When used as nouns, butt cheek means a buttock, whereas cheek means the soft skin on each side of the face, below the eyes.

Cheek is also verb with the meaning: to be impudent towards.

check bellow for the other definitions of Butt cheek and Cheek

Cheek as a noun (anatomy):

The soft skin on each side of the face, below the eyes; the outer surface of the sides of the oral cavity.
Cheek as a noun (anatomy, informal, usually, in the plural):

A buttock.
Cheek as a noun (informal, uncountable):

Impudence.

Examples:

"You’ve got some cheek, asking me for money!"
Cheek as a noun (biology, informal):

One of the genae, flat areas on the sides of a trilobite's cephalon.
Cheek as a noun:

One of the pieces of a machine, or of timber or stonework, that form corresponding sides or a similar pair.

Examples:

"the cheeks of a vice; the cheeks of a gun carriage"
Cheek as a noun (in plural):

The branches of a bridle bit.

Examples:

"rfquotek Knight"
Cheek as a noun (metalworking):

The middle section of a flask, made so that it can be moved laterally, to permit the removal of the pattern from the mould.

Cheek as a verb:

To be impudent towards.

Examples:

"Don't cheek me, you little rascal!"