A few butterflies and many moth species spin a silk case or cocoon prior to pupating, while others do not, instead going underground. A butterfly pupa, called a chrysalis, has a hard skin, usually with no cocoon.
4. tension - (physics) a stress that produces an elongation of an elastic physical body; the direction of maximum tension moves asymptotically toward the direction of the shear. natural philosophy, physics-the science of matter and energy and their interactions; his favorite subject was physics.
If you buy your girlfriend a vacuum cleaner when she wanted diamonds, you will experience tension. Just before she storms out of the room. The noun tension has its Latin roots in tendere, which means to stretch, and tension occurs when something is stretched either physically or emotionally. Strained relations between countries can cause political tensions to rise. You can add tension to a rubber band by stretching it tight.