A crustose lichen with small upward-pointing fruiting bodies supposed to resemble dressmakers' pins. They include members of the genera Calicium and Chaenotheca.

plural of pin lichen

(informal) Miniature Pinscher

(aviation, slang) The lock pin used to help secure the Jesus nut of some helicopters.

(neologism) A Pinoy or Pinay; an ethnic Filipino.

plural of Pin@y

(colloquial) To opt out; to withdraw; to resign.

(UK) (simile) Very neat and tidy.

(construction) A pin with a hooked head, used to pin together the frame of a floor or roof.

(dated) A curling iron.