(usually in Sino-Tibetan linguistics) a linguistic form (attested or reconstructed word) which belongs to a particular word family. For example, Proto-Sino-Tibetan *r-na would be the allofam from *r/g-na which gave rise to Tibetan rna ("ear").
allo- + fam, the latter the abbreviation of family.
English Wiktionary. Available under CC-BY-SA license.