What is Pin ?
Pin is (noun) 1. a small thin sharp metal stick with a round head, used for fastening things such as pieces of cloth or paper together She fastened the ribbons to her dress with a pin. 2. a thin wooden or metal bar used for fastening things together After the accident, he had to have two pins inserted in his leg. (verb) 1. to attach with a pin She pinned up a notice about the meeting. He pinned her photograph on the wall. He pinned the calendar to the wall by his desk. 2. to force someone to stay in a place, either deliberately or because of an accident Several people were pinned under the fallen roof. The car pinned her against the wall. (NOTE: pinning pinned)
source: Easier English, Student Dictionary Upper Intermediate Level