constrict

Constrict is a verb that means to draw tight, make narrower, or press inwards by squeezing. It can also mean to limit or restrict something. The term derives from the Latin constringere ('to bind together tightly').

In anatomy and physiology, constriction refers to the narrowing of a passage or vessel due to muscular activity. Examples include vasoconstriction, the narrowing of blood vessels; bronchoconstriction, the narrowing of airways; and the action of sphincters that constrict to control the passage of substances.

In zoology, constrict refers to a method used by some snakes to subdue prey. Constrictor snakes coil around their catch and tighten their grip, cutting off circulation and respiration. The boa constrictor is a well-known example.

In engineering and fluid dynamics, constrictions are narrowed sections of pipes or channels that influence flow rate and pressure. A constriction can create turbulence or increase velocity in a fluid and is analyzed in principles such as the Bernoulli and continuity equations.

Figure uses include describing limits or restraints, as in constricting budgets, movements, or freedoms. The related noun constriction denotes the act or condition of becoming narrowed.