identity element

/ ī-dĕn′tĭ-tē /

1. The element of a set of numbers that when combined with another number under a particular binary operation leaves the second number unchanged. For example, 0 is the identity element under addition for the real numbers, since for any real number a, a + 0 = a, and 1 is the identity element under multiplication for the real numbers, since a × 1 = a.

Example Sentences

The trouble is this: when “leftism” becomes an identity element, it makes leftist politics involuntary.

From The Daily Beast