Comments: PAT *mǝʕʷa; PAK *ʁʷa-gʷǝ́ (a compound of *ʁʷa 'road' + *gʷǝ 'surface, centre < *heart'); Ub. def. á-mʁ́a.
All attempts to etymologise the AK word from inside (treating *ʁʷa as 'dry' [Яковлев 1941, Kuipers 1960] or 'hole' [Aбитов 1948]) are unacceptable; see Shagirov 1, 132-133.
