1 undir-heimar
m. pl. the nether world, the realm below, Fms. iii. 178, Fas. iii. 391.
2 undir-heimar
2. in Icel. undirheimar is a name given to the lower beach between a reef of rocks and the sea; fara ofan í undirheima, hann er niðri í undirheimum.