"Pin" means several different things:

Fasteners and accessories:

• pin_fastener — Used to hold something in place.
• bobby_pin — Used to keep hair in place.
• clothes_pin — Used to hang clothing on a clothes line.
• safety_pin — Has a spring mechanism and a clasp.
• thumb_tack (drawing pin) — Used to fasten objects to a wall or board for display.
• sewing_pin — Used to hold fabric in position while sewing, a thin metal pin with a ball or T on its end.
• pin_accessory — Jewelry and decorations known as "pins".
• lapel_pin — Usually worn on the lapel of a dress jacket, but also popular as a themed collectible that can be traded.
• flag_pin — A variant of lapel pins that is modeled after a country's or organization's flag. Usually worn by politicians.
• pin_button — A round, decorative badge fastened onto clothing by a safety pin.

Other meanings:

• bowling_pin — One of the main components of bowling; set them up, knock them down.
• rolling_pin — Used to flatten dough and other uncooked or unbaked foods.
• pinned — To be held down by a character during sex, or a method an opponent uses to win a wrestling match.
• pinned_arms — A character is held down by their arms.
• pin_the_tail_on_the_donkey — A children's game where a blindfolded person has to pin a fake tail on an ass.
• pinup — Artwork of a posed model.