A constriction is a tight squeeze. If you have asthma, you know that the constriction of the airways makes it hard to breathe. If you’re a snake, you know that the constriction of a mouse makes a good dinner.
The word constriction comes from the Latin constringere for "compress," which is what constrictions do. If a hose is running and you squeeze it in the middle, that constriction cuts off the flow. A highway that goes from four lanes to one causes a constriction, or bottleneck. A constriction can also be a tight feeling in your body. If you’re afraid there’s a boa constrictor under your bed, you might feel a constriction in your chest.