maˀnat- - the entire part of the belly that surrounds the navel
(BK 2 1054)
Vestiges of -ˀ- in Arb. rather point to *-ˀ- in the protoform; otherwise a biconsonantal root, with insertion of -ˀ as a second radical in Arb. What is meant is probably rectus abdominis, a straight muscle of the abdomen.