before vowels gloss-, word-forming element meaning "tongue," from Greek glosso-, used as a combining form of glōssa (Attic glōtta) "tongue" (see gloss (n.2)). Also sometimes meaning "gloss, word inserted as explanation," as in glossography "the writing of glosses."
Entries linking to glosso-
gloss n.2
"word inserted as an explanation, translation, or definition," c. 1300, glose (modern form from 1540s; earlier also gloze), from Late Latin glossa "obsolete or foreign word," one that requires explanation; later extended to the explanation itself, from Greek glōssa (Ionic), glōtta (Attic) "language, a tongue; word of mouth, hearsay," also "obscure or foreign word, language," also "mouthpiece," literally "the tongue" (as the organ of speech), from PIE *glogh- "thorn, point, that which is projected" (source also of Old Church Slavonic glogu "thorn," Greek glokhis "barb of an arrow").
Glosses were common in the Middle Ages, usually rendering Hebrew, Greek, or Latin words into vernacular Germanic, Celtic, or Romanic. Originally written between the lines, later in the margins. By early 14c. in a bad sense, "deceitful explanation, commentary that disguises or shifts meaning." This sense probably has been colored by gloss (n.1). Both glossology (1716) and glottology (1841) have been used in the sense "science of language."
glossalgia n.
"pain in the tongue," 1847, medical Latin, from glosso- "tongue" + -algia "pain." Greek glossalgia meant only "talking till one's tongue aches."