Meaning of “pin sth up” - Learner’s Dictionary

pin sth up

phrasal verb with pin us uk /pɪn/ verb [ T ] present participle pinning, past tense and past participle pinned

to fasten something to a wall using a pin:

The exam results have been pinned up on the noticeboard.

(Definition of “pin sth up” from the Cambridge Learner’s Dictionary © Cambridge University Press)