perforation

Short definition from Wiktionary

Noun

1. 1
   The act of perforating or the state of being perforated.
2. 2
   Any opening in a solid object.
3. 3
   An abnormal opening in an organ, such as a rupture.
4. 4
   A series of holes punched through something in order to assist in separating parts.
5. 5
   That portion of a surface that remains after an open disk is removed from it.