Antikythera mechanism, an ancient Greek analog computer

Defence mechanism, unconscious mechanisms aimed at reducing anxiety

Mechanism (philosophy), a theory that all natural phenomena can be explained by physical causes

Reaction mechanism, the sequence of reactions by which overall chemical change occurs

Mechanism design, the art of designing rules of a game to achieve a specific outcome

Mechanism (biology), explaining how a feature is created.

Mechanism (horology), a piece of a time-keeping device

Mechanism of action, the means by which a drug exerts its biological effects

Mechanism (technology), a device of which a mechanical joint is used

Mechanism (sociology), a set of rules designed to bring about a certain outcome