Definitions for PERF
perforation or perforated. When followed by a number, eg, perf 14, this indicates the number of perforations per two centimetres.
The New Hacker's Dictionary
Syn. chad (sense 1). The term perfory /per´f@-ree/ is also heard. The term perf may also refer to the perforations themselves, rather than the chad they produce when torn (philatelists use it this way).