per·fo·ra·tion /ˌpɝfəˈreʃən/ 名詞
1. The act of perforating, or of boring or piercing through.
2. A hole made by boring or piercing; an aperture. “Slender perforations.”
n 1: a line of small holes for tearing at a particular place
2: a hole made in something; "a perforation of the eardrum"
3: the act of punching a hole (especially a row of holes as for
ease of separation)