Getting a little pedantic 2. a large branch of a tree. "the bare limbs of a high tree" Similar: branch

limb (n.2) late 14c., "edge of a quadrant or other instrument," from Latin limbus "ornamental border, hem, fringe, edge," a word of uncertain origin.

Just thought of the limbic system and how that might be related, doesn't seem to be about function but about positioning against a core system