þinaz

þinaz is a reconstructed Proto-Germanic noun form used in historical linguistics to discuss the lexicon of the ancestor language of the Germanic families. The form is written with thorn (þ) to reflect the reconstructed phoneme and is usually presented as a masculine nominative singular with the typical Proto-Germanic ending -az. In scholarly works, such forms are used as placeholders to illustrate noun formation and phonology, not as attested words in primary sources.

Most reconstructions that employ þinaz associate it with a semantic field related to the body, commonly linked to the word for "tooth." The proposed gloss is "tooth," based on cognates across Germanic languages, such as Old English toþ (tooth), Old Norse tönn, and Old High German zahn. However, semantic assignments in Proto-Germanic reconstructions are inherently uncertain, and not all scholars endorse this particular meaning. The form is mainly of interest as an instructional example of how stem, gender, and endings cohere in Proto-Germanic morphology rather than as a securely established lexeme.

Direct attestation of þinaz in ancient texts or inscriptions is lacking. It appears instead in linguistic reference works as a hypothetical form used to demonstrate the nominal paradigm and the historical phonology that produced its descendants in later Germanic languages. As with many reconstructed forms, its exact interpretation may vary among researchers.

See also: Proto-Germanic language, Old English, Old Norse, Old High German; glyphs and runic alphabets; lexicography in historical linguistics.