- any seaweed of the genus Ulva, having large leaflike blades.
Origin of sea lettuce
First recorded in 1660–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for sea lettuce
There is sea-lettuce in the water, so there must be enough air.
Ulva, or sea-lettuce, is to be found in abundance in all our small bays and inlets at low tide.
- any of various green seaweeds of the genus Ulva, which have edible wavy translucent fronds