Search Result for "rockweed": 
Wordnet 3.0

NOUN (1)

1. coarse brown seaweed growing on rocks exposed at low tide; 



The Collaborative International Dictionary of English v.0.48:

Rockweed \Rock"weed`\, n. (Bot.)
   Any coarse seaweed growing on sea-washed rocks, especially
   Fucus.
   [1913 Webster]


WordNet (r) 3.0 (2006):

rockweed
    n 1: coarse brown seaweed growing on rocks exposed at low tide