permanent

A chemical hair treatment imparting or removing curliness, whose effects typically last for a period of weeks; a perm.

Given an n \times n matrix a_{ij} \,, the sum over all permutations \pi \, of \prod_{i=1}^n{a_{i\pi(i)}}.

(trading card games) A card whose effects persist beyond the turn on which it is played.

To perm (the hair).

Without end, eternal.

"Nothing in this world is truly permanent."

Lasting for an indefinitely long time.

"The countries are now locked in a permanent state of conflict."