Peg is a short pin or bolt, usually made of wood or metal, that holds things together or marks a position. You might hang your coat on a peg by the door, or use wooden pegs to attach the sides of a birdhouse you're building. Before metal screws became common, carpenters joined furniture using carefully shaped wooden pegs that fit snugly into drilled holes.

Pegs serve as anchors and markers in many situations. When you play cribbage, you move pegs along holes in a board to track your score. When camping, you peg down a tent by hammering pegs through loops in the fabric into the ground. Climbers sometimes place metal pegs (also called pitons) into rock cracks to secure their ropes.

The word also works as a verb. To peg something means to fasten it with pegs, or to identify and categorize someone. If a teacher quickly pegs you as a strong reader, she's recognized that skill of yours.

A square peg in a round hole describes someone who doesn't quite fit their situation, like an artistic kid in a school that only values math and science.