Synonyms for Eyehole (same or very similar meaning)
WordNet sense 1 (a hole (in a door or an oven etc) through which you can peep):
peephole, spyholeWordNet sense 2 (a small hole (usually round and finished around the edges) in cloth or leather for the passage of a cord or hook or bar):
eyeletFrom the ODE community, based on WordNetadd/edit