evacuation

Short definition from Wiktionary

Noun

1. 1
   The act of evacuating; leaving a place in an orderly fashion, especially for safety.
2. 2
   Withdrawal of troops or civils from a town, country, fortress, etc.
3. 3
   The act of emptying, clearing of the contents, or discharging, including creating a vacuum.
4. 4
   Voidance of any matter by the natural passages of the body or by an artificial opening; defecation; urination; also, a diminution of the fluids of an animal body by cathartics, venesection, or other means.
5. 5
   That which is evacuated or discharged; especially, a discharge by stool, urine or other natural means.
6. 6
   Abolition; nullification.