*aluþ

A neuter consonant stem of uncertain deeper etymology, usually compared with Proto-Indo-European *h₂elut-. Kroonen (2013: 23–24) notes that no generally accepted etymology exists. Bjorvand (2007) derives Germanic *alú-þ- from earlier *olú-t-, and connects *alu- with Vedic Sanskrit अ॒रु॒ष (aruṣá), Avestan 𐬀𐬎𐬭𐬎𐬱𐬀 (auruša), and Old High German elo, hence originally ‘golden/pale beverage’. Possible inherited cognates include Old Armenian աւղի (awłi) (Olsen 1999: 443) and Lithuanian alùs. Derksen (2015: s.v. alus) notes that the Baltic and Slavic forms may be borrowings from Germanic, but Jakob (2024: 41) specifically rejects the widespread analysis of the latter as a Germanic loan, since a donor *aluþ- should have preserved some trace of the stem-final dental. Proto-Finnic *olut, by contrast, is most plausibly derived from late Proto-Scandinavian **ǫluþ-, after *a had been rounded but before loss of the second syllable, providing strong evidence for the dental stem at that stage (Junttila et al. 2020–: s.v. olut). Ossetian ӕлутон (æluton) has been treated as a Germanic loan by Kroonen but as an inherited cognate by Bjorvand (Bjorvand 2007; Kroonen 2013: 23–24). Alternatively, the European beer words may belong with Latin alūmen through *alu- ‘bitter substance’, perhaps ultimately from a European substrate (de Vaan 2008: 36).