"sea-eagle, osprey," c.1600, from Latin ossifraga "vulture," fem. of ossifragus, literally "bone-breaker," from ossifragus (adj.) "bone-breaking," from os (genitive ossis) "bone" (see osseous) + stem of frangere "to break" (see fraction). By this name Pliny meant the lammergeier (from German, literally "lamb-vulture"), a very large Old World vulture that swallows and digests bones and was believed also to drop them from aloft to break them and get at the marrow. But in England and France, the word was transferred to the osprey, perhaps on similarity of sound between the two words.
Heb. peres = to "break" or "crush", the lammer-geier, or bearded vulture, the largest of the whole vulture tribe. It was an unclean bird (Lev. 11:13; Deut. 14:12). It is not a gregarious bird, and is found but rarely in Palestine. "When the other vultures have picked the flesh off any animal, he comes in at the end of the feast, and swallows the bones, or breaks them, and swallows the pieces if he cannot otherwise extract the marrow. The bones he cracks [hence the appropriateness of the name ossifrage, i.e., "bone-breaker"] by letting them fall on a rock from a great height. He does not, however, confine himself to these delicacies, but whenever he has an opportunity will devour lambs, kids, or hares. These he generally obtains by pushing them over cliffs, when he has watched his opportunity; and he has been known to attack men while climbing rocks, and dash them against the bottom. But tortoises and serpents are his ordinary food...No doubt it was a lammer-geier that mistook the bald head of the poet AEschylus for a stone, and dropped on it the tortoise which killed him" (Tristram's Nat. Hist.).