[fyoo-kuh
s] 
[-sahy] , -cus⋅es. | any olive-brown seaweed or alga of the genus Fucus, having branching fronds and often air bladders. |
| fu·cus (fyōō'kəs) n. Any of various brown algae of the genus Fucus, which includes many of the rockweeds. [Latin fūcus, seaweed, orchil, from Greek phūkos.] |