Adjective

1. Having lost its freshness from age. Stale food, for instance, is food which is still edible but has lost its deliciousness.

   The steak is as stale as the beer.

   If you don't enter a room for some days, the air will become stale.

2. No longer new; no longer interesting; established; old; as, stale news, a stale joke, etc.

Noun

1. A woman who is “no longer fresh” or who has lost her virginity.
   • Shakespeare, Much Ado About Nothing, Act IV, Scene i, lines 59-60:

     I stand dishonor'd, that have gone about

     To link my dear friend to a common stale

Etymology 2

Noun

1. A person's position, especially in a battle-line.
   • 1485, Sir Thomas Malory, Le Morte Darthur, Book V:

     for ony stowre that ever ye see us bestadde, stondys in your stale and sterte ye no ferther.

2. An ambush.
3. A division of armed men posted in a specific place, either for an ambush or for other reasons.