tension

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of stretching something tight.
• noun The condition of so being stretched; tautness.
• noun A force tending to stretch or elongate something.
• noun A measure of such a force.
• noun Mental, emotional, or nervous strain.
• noun Barely controlled hostility or a strained relationship between people or groups.
• noun A balanced relation between strongly opposing elements.
• noun The interplay of conflicting elements in a piece of literature, especially a poem.
• noun A device for regulating tautness, especially a device that controls the tautness of thread on a sewing machine or loom.
• noun Electricity Voltage or potential; electromotive force.
• transitive verb To subject to tension; tighten.

from The Century Dictionary.

• noun In phytogeography, same as tension-line.
• To make tense; give the right degree of tension to; draw out; strain.
• noun The act of stretching, straining, or making tense; the state of being stretched or strained to stiffness; the condition of being bent or strained.
• noun In mech., stress, or the force by which a bar, rod, string, or the like is pulled when forming part of any system in equilibrium or in motion.
• noun In physics. a constrained condition of the particles of bodies, arising from the action of antagonistic forces, in which they tend to return to their former condition; elastic force.
• noun In statical elect., the mechanical stress across a dielectric, due to accumulated charges, as in a condenser; hence, the same as surface-density (the amount of electricity at any point of the surface of a charged conductor); more commonly used, in dynamical electricity, to mean about the same as difference of potential: thus, a current of high tension is popularly a current of high electromotive force.
• noun Mental strain, stretch, or application; strong or severe intellectual effort; strong excitement of feeling; great activity or strain of the emotions or the will.
• noun A strained state of any kind: as, political tension; social tension.
• noun An attachment to a sewing-machine for regulating the strain of the thread.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of stretching or straining; the state of being stretched or strained to stiffness; the state of being bent strained.
• noun Fig.: Extreme strain of mind or excitement of feeling; intense effort.
• noun The degree of stretching to which a wire, cord, piece of timber, or the like, is strained by drawing it in the direction of its length; strain.
• noun (Mech.) The force by which a part is pulled when forming part of any system in equilibrium or in motion.
• noun A device for checking the delivery of the thread in a sewing machine, so as to give the stitch the required degree of tightness.
• noun (Physics) Expansive force; the force with which the particles of a body, as a gas, tend to recede from each other and occupy a larger space; elastic force; elasticity.
• noun (Elec.) The quality in consequence of which an electric charge tends to discharge itself, as into the air by a spark, or to pass from a body of greater to one of less electrical potential. It varies as the quantity of electricity upon a given area.
• noun (Engin.) a brace or member designed to resist tension, or subjected to tension, in a structure.
• noun (Engin.) an iron rod used as a tension member to strengthen timber or metal framework, roofs, or the like.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Psychological state of being tense.
• noun Condition of being held in a state between two or more forces, which are acting in opposition to each other
• noun physics (engineering) State of an elastic object which is stretched in a way which increases its length.
• noun physics (engineering) Force transmitted through a rope, string, cable, or similar object (used with prepositions on, in, or of, e.g., "The tension in the cable is 1000 N", to convey that the same magnitude of force applies to objects attached to both ends).
• noun physics Voltage. Usually only the terms low tension, high tension, and extra-high tension, and the abbreviations LT, HT, and EHT are used. They are not precisely defined; LT is normally a few volts, HT a few hundreds of volts, and EHT thousands of volts.
• verb To place an object in tension, to pull or place strain on.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a balance between and interplay of opposing elements or tendencies (especially in art or literature)
• noun (physics) a stress that produces an elongation of an elastic physical body
• noun the action of stretching something tight
• noun the physical condition of being stretched or strained
• noun feelings of hostility that are not manifest
• noun (psychology) a state of mental or emotional strain or suspense