2 definitions
for Ulva
From The Collaborative International Dictionary of English v.0.48 :
Ulva \Ul"va\, prop. n. [L., sedge.] (Bot.)
A genus of thin papery bright green seaweeds including the
kinds called sea lettuce.
[1913 Webster]
From WordNet (r) 2.0 :
Ulva
n : type genus of the family Ulvaceae; green seaweed having a
thallus two cells thick: sea lettuce [syn: genus Ulva]