Proto-Indo-European root meaning "bone."
It forms all or part of: osseous; ossicle; ossuary; ossifrage; ossify; osteo-; osteology; osteopathy; ostracism; ostracize; oyster; periosteum.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit asthi, Hittite hashtai-, Greek osteon "bone," Greek ostrakon "oyster shell," Avestan ascu- "shinbone," Latin os (genitive ossis) "bone," osseus "bony, of bone," Welsh asgwrn, Armenian oskr, Albanian asht "bone."