http://www.thefreedictionary.com/stale
1. Having lost freshness, effervescence, or palatability: stale bread; stale air.
2. Lacking originality or spontaneity: a stale joke.
3. Impaired in efficacy, vigor, or spirit, as from inactivity or boredom.
4. Law Having lost effectiveness or force through lack of exercise or action.
intr.v.staled, stal·ing, stales
To urinate. Used especially of horses and camels.
n.
The urine of certain animals, especially horses and camels
http://en.wikipedia.org/wiki/Staling
Staling, or “going stale”, is a chemical and physical process in bread and other foods that reduces their palatability. Stale bread is dry and leathery.
Staling is not, as is commonly believed, simply a drying-out process due to evaporation. Bread will stale even in a moist environment, and stales most rapidly at temperatures just above freezing.