When workers go on strike to protest their employer, they often form a picket line outside their workplace, where they walk back and forth carrying signs explaining their grievances. This act of protesting is called picketing. The workers themselves are called pickets.

Picket lines serve two purposes: they make the public aware of the workers' complaints, and they discourage other workers from crossing the line to go to work. When a factory's workers are picketing, they might carry signs demanding better pay or safer working conditions. The line of protesters creates a visible barrier that other employees must decide whether to cross.

The word can also mean a pointed wooden stake driven into the ground. A picket fence is made of these vertical stakes placed side by side, creating the classic white fences you might see around houses. Soldiers sometimes use pickets to secure tents or mark boundaries. During the American Civil War, soldiers placed pickets around their camps as early-warning sentries, which is why guards on the outer edge of a camp are still sometimes called pickets.

The two meanings share a common idea: standing as a marker or barrier in a specific spot. Whether it's workers standing firm outside a building or wooden stakes standing upright in the ground, pickets hold their position.