nerve

A bundle of neurons with their connective tissue sheaths, blood vessels and lymphatics.

"The nerves can be seen through the skin."

A neuron.

A vein in a leaf; a grain in wood

"Some plants have ornamental value because of their contrasting nerves."

Courage, boldness.

"He hasn't the nerve to tell her he likes her. What a wimp!"

To give courage.

"May their example nerve us to face the enemy."

To give strength; to supply energy or vigour.

"The liquor nerved up several of the men after their icy march."