What is the meaning of Idempotent?

Such that, when performed multiple times on the same subject, it has no further effect on its subject after the first time it is performed.

Such that, when it operates on itself, the result is equal to itself.

Such that all of the distinct elements it can operate on are idempotent .

Having an idempotent operation .

An idempotent element.

An idempotent structure.

idempotent

idempotent

idempotent

idempotent

Source: wiktionary.org