In anatomy, a limb was an appendage of the body, including arms and legs.
In their natural form, Kelvans were described as immense beings with hundreds of limbs resembling tentacles, who possessed such advanced minds they could allow control of each limb to perform a different function. (TOS: "By Any Other Name")
The leaders of Fendaus V were born without limbs. (TNG: "Loud As A Whisper")
A broken limb could be kept immobile by a splint, which allowed it to heal. (TNG: "Contagion")