Plaque is a thing — a metal or stone panel on a wall, or the film that builds up on teeth. Plague is a disease or a serious, spreading problem, and can also be a verb meaning to trouble persistently. Memory hook: a plaque hangs flat on a wall, a plague spreads and strikes.
The core difference
Plaque is a flat, fixed object or deposit, while plague is a deadly disease or a persistent, spreading trouble.
- plaque — a commemorative panel, or a film that builds up on teeth or in arteries: A bronze plaque marks the house where the poet was born.
- plague — a deadly, fast-spreading disease, or a widespread serious problem: A plague of locusts destroyed the entire harvest.
- plague (verb) — to trouble or afflict someone persistently: Injuries have plagued the team all season.
How to tell them apart
The two words look alike because they share a French and Latin ancestry, but their meanings pull in different directions. Plaque comes from a root meaning "plate" or "slab" — think of a bronze plaque as a small flat plate fixed to a wall, and dental plaque as a thin film sitting flat on a tooth's surface.
Plague comes from a Latin word for a blow or a wound, which fits its sense of something striking and spreading, whether that is the historical disease or a run of bad luck described as "plaguing" someone. If the word names an object you could hold flat in your hand or find in your mouth, it is plaque; if it names a disease or an ongoing affliction, it is plague.
