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.
Top definition. Tension. In modeling, it refers to the state of exhibiting intense fierceness with one's face and body during a photo shoot. One who does not exhibit tension can be said to resemble a limp noodle. It quickly became a favorite term of supermodel Tyra Banks on the twelfth cycle of America's Next Top Model, much to everyone's annoyance. For more examples of Tyraspeak, see smize, H2T, and Ty-over.