saltpeter n.

Proto-Indo-European root meaning "salt."

It forms all or part of: hali-; halide; halieutic; halite; halo-; halogen; sal; salad; salami; salary; saline; salmagundi; salsa; salsify; salt; salt-cellar; saltpeter; sauce; sausage; silt; souse.

It is the hypothetical source of/evidence for its existence is provided by: Greek hals "salt, sea;" Latin sal, Old Church Slavonic soli, Old Irish salann, Welsh halen, Old English sealt, German Salz "salt."

c. 1400, in anatomy, "very hard, dense," from Old French petros (Modern French petreux) and directly from Latin petrosus "stony," from petra "rock," from Greek petra "rock, cliff, ledge, shelf of rock, rocky ridge," a word of unknown etymology (Beekes says it is "probably Pre-Greek"). Used of certain bones, especially of parts of the temporal bone.

chiefly British English spelling of saltpeter (q.v.); for ending, see -re.