Other forms: limbs
A limb is an arm or a leg — one word covering all four. Lost a limb, a broken limb, stretch your limbs.
The b is silent. It is the medical and formal word: prosthetic limb, limb injury, upper and lower limbs. A limb is also a large branch of a tree, which is the older sense and gives the phrase out on a limb — meaning in an exposed position with no support, from somebody who has climbed too far along a branch. Note limbs in the plural, which sounds literary in ordinary speech.
1nounlimbAn arm or a leg.
“He lost the use of one limb and taught himself to write again.”
2nounlargeA large branch of a tree.
“A limb came down across the whole drive.”
limb is an arm, leg or branch.
Old English lim meant a limb or a branch, with no b at all. The b was added by sixteenth-century writers on the model of climb and thumb, and has never been pronounced by anybody.
Proto-Germanic
*limuz — branch, limb
Proto-West Germanic
*limu
Old English
lim — limb, branch
Middle English
lyme
English, today
limb
From Middle English lyme, lim, from Old English lim (“limb, branch”), from Proto-West Germanic limu, from Proto-Germanic limuz (“branch, limb”). Cognate with Old Norse limr (“limb”). The spelling with the silent unetymological -b first arose in the late 1500s. Compare crumb.
Etymology from Wiktionary, CC BY-SA