Definition of: pin

(pin) noun
1. A short stiff piece of wire, with a sharp point and a round, usually flattened head, used in fastening together parts of clothing, sheets of paper, etc.
2. An ornamental device mounted on a pin or having a pin as a clasp: often serving to fasten parts of the dress in addition to its use as a decoration: frequently a badge.
3. A peg or bar of metal or wood used for a fastening or support, as the thole of a boat, the bolt of a door, a peg serving to stop a hole or to fasten two beams together, or to keep a wheel from slipping from an axle, or one of the pegs to which the strings of a musical instrument are fastened.
4. Anything like a pin, as a hairpin or clothespin.
5. Usually plural A wooden club turned in long, oval, or cylindrical shape, set up as a mark or target in various bowling or ball–throwing games; a skittle.
6. plural Colloq. Legs.
7. A belaying–pin; a rolling pin; a thole pin.
8. The merest trifle.
9. The cylindrical part of a key forward of the stem that enters the lock.
10. Obs. A peg showing the center of a target.
—v.t. pinned, pin·ning
1. To fasten with a pin or pins.
2. To transfix with a pin, spear, etc.
3. To seize and hold firmly: to pin an opponent against a wall.
4. To force (someone) to make a definite statement, abide by a promise, etc.: usually with down. [OE pinn a peg,? ult. <L pinna a point, pinnacle]
PINS OF VARIOUS TYPES
a. Greek.
b. Roman.
c. Early French.
d. Russian.
e. Scandinavian.
f. Safety pin.
g. Hairpins.
h. Round–headed.
i. Hatpin.