ten·sion 
(tĕnshən)
(tĕnshən)n.
1.
a. The act or process of stretching something tight.
b. The condition of so being stretched; tautness.
2.
a. A force tending to stretch or elongate something.
b. A measure of such a force: a tension on the cable of 50 pounds.
3.
a. Mental, emotional, or nervous strain: working under great tension to make a deadline.
b. Barely controlled hostility or a strained relationship between people or groups: the dangerous tension between opposing military powers.
4. A balanced relation between strongly opposing elements: "the continuing, and essential, tension between two of the three branches of government, judicial and legislative" (Haynes Johnson).
5. The interplay of conflicting elements in a piece of literature, especially a poem.
6. A device for regulating tautness, especially a device that controls the tautness of thread on a sewing machine or loom.
7. Electricity Voltage or potential; electromotive force.
tr.v. ten·sioned, ten·sion·ing, ten·sions
To subject to tension; tighten.
[Latin tēnsiō, tēnsiōn-, a stretching out, from tēnsus, past participle of tendere, to stretch; see TENSE1.]
tension·al adj.