According to both sources, from SUM šà.mah_ 'Dickdarm' [AHw 1156], which, if not for a striking GEZ cognate, would look convincing (SUM šà 'Bauch, Darm, etc.' [IK 922], mah_ 'gross, etc.' [ibid. 651]); anyway, the coincidence of apparently independent SEM (AKK and GEZ) and SUM terms is fascinating

    Cf. ARM JUD summǝḳā 'milt' (also 'inflammation of the eye', evidently a homonym) [Ja 966]; cf. also ARB samāḥīḳ- (pl.) 'stries, raies, surtout filets de graisse collés aus intestins chez les moutons' [BK 1 1136]. Though not to be directly compared for phonetic reasons, these terms apparently bear certain, probably not accidental, similarity to the present root.

    [Holma 83]: "Ich glaube, šamah_h_u ergibt sich als ein echtsemitisches Wort wenn man es äthiop. sǝmāh_ 'Milz' zusammenstellt"