·noun A composite plant of the genus Lactuca (L. sativa), the leaves of which are used as salad. Plants of this genus yield a milky juice, from which lactucarium is obtained. The commonest wild lettuce of the United States is L. Canadensis.
·- The green papery fronds of several seaweeds of the genus Ulva, sometimes used as food. ...
Webster's Dictionary of the English Language
·- A plant (Pistia stratiotes) which floats on tropical waters, and forms a rosette of spongy, wedge...
The edible sea-weed Ulva lactuca. ...
The Sailor's Word-Book