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.
Use tension in a sentence. LINK / CITE ADD TO WORD LIST. noun. Tension is physical or mental strain, the force created by pulling something tight or a strain in a relationship. 1  An example of tension is the feeling of working to meet an established deadline. 2  An example of tension is pulling the two ends of a rubber band further and further apart from each other.