- a floating aquatic plant, Pistia stratiotes, of the arum family, having a rosette of thick, spongy leaves.
Origin of water lettuce
First recorded in 1865–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for water lettuce
Like the lake, it has great patches of water-lettuce, which in some places almost bridge the channel.
This is principally formed of the water-lettuce, or Pistia, an aquatic plant with long roots which descend to the bottom.