a bony spine (something resembling a backbone, such as a ridge, or a long, central structure from which other structures radiate)

a coracoid (small bone linking the scapula and sternum in birds, reptiles and some other vertebrates)

bone conduction

(idiomatic) to look after someone's affairs after someone dies / to collect ashes of the deceased

osteology

osteologist

Kyūjitai form of 骨学: osteology

(idiomatic) tears (drops from the eyes)

(informal) "not knowing even a millimeter": completely ignorant in regards to something

crēdō ut intelligam