A number used to multiply a variable.

Example: 6z means 6 times z, and "z" is a variable, so 6 is a coefficient.

Variables with no number have a coefficient of 1.

Example: x is really 1x.

Sometimes a letter stands in for the number.

Example: In ax^{2} + bx + c, "x" is a variable, and "a" and "b" are coefficients.

See: Variable