ost- / Indo-European roots
Examples of words with the root ost-: astaxanthin, astragal, astragalus, endosteum, exostosis, os, osseous, ossicle, ossicone, ossifrage, ossify, ossuary, osteo-, osteon, ostracize, ostracod, ostracoderm, ostracon, oyster, periosteum, periostracum, synostosis, teleost.
Bone.Oldest form *h2ost-, with e-grade *h2est- colored to *h2ast-.
1. os2, osseous, ossicle, ossuary; ossifrage, ossify from Latin os (stem oss-), bone.
2. osteo-, osteon; endosteum, exostosis, periosteum, synostosis, teleost from Greek osteon, bone.
3. Suffixed form *ost-r-.
a. ostracize, ostracod, ostracon; ostracoderm, periostracum from Greek ostrakon, shell, potsherd;
b. e-grade form *əest-, becoming *ast-. oyster from Greek ostreon, oyster;
c. astragal, astragalus from Greek astragalos, vertebra, ball of the ankle joint, knucklebone, Ionic molding.
4. Suffixed form *ost-n̥-ko-. astaxanthin from Greek ostakos, astakos, lobster.
[Pokorny ost(h)- 783.]