"young of a bovine animal," Old English cealf (Anglian cælf) "young cow," from Proto-Germanic *kalbam (source also of Middle Dutch calf, Old Norse kalfr, German Kalb, Gothic kalbo), perhaps from PIE *gelb(h)-, from root *gel- "to swell," hence, "womb, fetus, young of an animal."
Elliptical sense of "fine kind of leather made from the skin of a calf" is from 1727 (short for calf-skin, 1580s). Extended by 1725 to the young of marine mammals, the adults of which are called bulls and cows. Used of icebergs that break off from glaciers from 1818 (perhaps from Scandinavian use in reference to a small islet lying near a large one). Finnish kalpe is from Germanic. Golden calf "idol" is from Exodus.