igenoun
igenoun is a linguistic concept referring to a hypothetical noun that would have existed in an ancient Indo-European language but is not directly attested in any surviving daughter languages. These reconstructed nouns are inferred from patterns in the phonology and morphology of known Indo-European languages. Linguists propose the existence of igenouns to explain sound changes and grammatical relationships that would otherwise be difficult to account for. For example, the presence of certain consonant clusters or vowel alternations in multiple branches of the Indo-European family might suggest a common ancestral form that has since undergone different developments.
The reconstruction of igenouns is a crucial part of comparative linguistics. By comparing related words across