Areal reconstruction

*š/sVn(-ām)- - hump of animal (camel, etc.) (SED I No. 250)

Problematic. Scarce attestation in the South Semitic area only; quality of the first radical unspecified.

Arabic
sinsinat- - camel hump summit (BK 1 1151)

Note a reduplicated stem and suffixed -m.

Geez
sə/anām - hump of animal (CDG 507)

Probably, an Arabism (suffix -m).

Tigre
səlam - hump of camel or of cattle (WTS 168)

Dissimilation from *sənam. An Arabism?

Argobba
šan̄n̄a - hump of animal (LArg. 221)

Hardle Cushitism (in view of the Sem. data), however, a borrowing from Arb. sanām- ‘camel hump’ is not impossible. 

Gogot
šan̄n̄a - hump of animal (LArg. 221)
Soddo
šan̄n̄a - hump of animal (LArg. 221)
Harsusi
sensīn ḏe-ḏ̣ahr - spine (HL 112)

lit. “spine of back”. Isolated in MSA, probably an Arabism.