From Proto-Indo-European*h₂én(“up, on high”), but the exact formation is disputed due to the final vowel in descendants that reflect *ana. According to Kroonen, who derives both *an and *ana from a pre-Germanic *h₂enh̥₂, the final vowel was lost by regular sound change but remained in compound forms, whence it was restored in some of the daughter languages.[1] Alternative explanations for the final vowel include a fossilized suffix *-o/*-ó of uncertain (allative?) function, as in *anda.