etymon

noun

1. The original or earlier form of an inherited or borrowed word, affix, or morpheme either from an earlier period in a language's development, from an ancestral language, or from a foreign language.

   “Here such cases as ghost words & misglosses, secondary semantics, different etymologies for one etymon or one etymology for different etyma, and finally semantic overpermissiveness are discussed.”

   “The resulting citation collection was databased and coded for meaning, etymon, and date range (earliest and latest occurrence found).”

   “Parricide, the more usual word, means (1) "the murder of one's own father"; or (2) "someone who murders his or her own father" […] It is also used in extended senses, such as "the murder of the ruler of a country" and "the murder of a close relative." These are not examples of slipshod extension, however, for even the Latin etymon (parricida) was used in these senses.”