wa·ka·me 
(wä-kämĕ)
(wä-kämĕ)n.
A brown seaweed (Undaria pinnatifida) native to East Asia and naturalized elsewhere, having a short stipe and pinnately divided blades, and used in Asian cooking.
[Japanese, from Old Japanese (perhaps originally meaning "young, soft seaweed harvested in spring" ) : possibly waka-, young + -me, seaweed (as in nikime, a kind of wakame).]