The Collaborative International Dictionary of English v.0.48:

Cuscus \Cus"cus\, n. [The same word as Couscous, fr. F.
   couscous couscous, Ar. kuskus.] (Bot.)
   A soft grass (Pennisetum typhoideum) found in all tropical
   regions, used as food for men and cattle in Central Africa.
   [Webster 1913 Suppl.]