Tension is the feeling of tightness, strain, or pressure that builds up in a situation or relationship. You feel tension in your shoulders when you're stressed about a big test, and you feel tension in the air when two friends have an argument but haven't talked about it yet. Physical tension makes your muscles tight and uncomfortable, while emotional tension makes you feel anxious or on edge.

Tension often appears in stories to keep readers interested. When the main character is hiding from danger or racing against time, that mounting pressure is tension. It makes you wonder what will happen next. A good mystery novel builds tension slowly, giving you clues but keeping you guessing until the final reveal.

In relationships, tension means there's an unresolved problem creating awkwardness or discomfort. Maybe two classmates both want to be team captain, or siblings are annoyed with each other but haven't said why. Sometimes tension gets released when people talk honestly about what's bothering them. Other times it keeps building until someone explodes in anger or frustration.

The word can also describe the tightness in a rope, wire, or string. A guitar string needs the right amount of tension to produce a clear note. Too loose and it sounds dull; too tight and it could snap.