Definition of pin

• v. t. - To peen.
• v. t. - To inclose; to confine; to pen; to pound.
• n. - A piece of wood, metal, etc., generally cylindrical, used for fastening separate articles together, or as a support by which one article may be suspended from another; a peg; a bolt.
• n. - Especially, a small, pointed and headed piece of brass or other wire (commonly tinned), largely used for fastening clothes, attaching papers, etc.
• n. - Hence, a thing of small value; a trifle.
• n. - That which resembles a pin in its form or use
• n. - A peg in musical instruments, for increasing or relaxing the tension of the strings.
• n. - A linchpin.
• n. - A rolling-pin.
• n. - A clothespin.
• n. - A short shaft, sometimes forming a bolt, a part of which serves as a journal.
• n. - The tenon of a dovetail joint.
• n. - One of a row of pegs in the side of an ancient drinking cup to mark how much each man should drink.
• n. - The bull's eye, or center, of a target; hence, the center.
• n. - Mood; humor.
• n. - Caligo. See Caligo.
• n. - An ornament, as a brooch or badge, fastened to the clothing by a pin; as, a Masonic pin.
• n. - The leg; as, to knock one off his pins.
• n. - To fasten with, or as with, a pin; to join; as, to pin a garment; to pin boards together.