scabbard

sphingolipid

myelin sheath (membrane surrounding axon of nerve cell)

(of a sword etc) to unsheath

Ascidiacea

(botany) leaf sheath

scabbard or sheath, for holding a sword, knife, or other large blade

elytrum (hardened forewing of Coleoptera beetle, encasing the flight wing)

(invertebrate zoology) ootheca

coleoptile, protective sheath covering an emerging shoot (botany)

(anatomy) tendon sheath

Coleoptera (insect order including beetles)

tenosynovitis (medicine)