What is Nerve?

Nerve definition and meaning on Dictionary terms:
one or more bundles of fibers forming part of a system that conveys impulses of sensation, motion, etc., between the brain or spinal cord and other parts of the body.
a sinew or tendon: to strain every nerve.
firmness or courage under trying circumstances: an assignment requiring nerve.
boldness; audacity; impudence; impertinence: He had the nerve to say that?
nerves, nervousness: an attack of nerves.

strength, vigor, or energy: a test of nerve and stamina.
(not in technical use) pulp tissue of a tooth.
Botany. a vein, as in a leaf.
a line, or one of a system of lines, extending across something.

verb (used with object), nerved, nerv