ETYM Old Eng. letuce, prob. through Old French from some Late Latin derivative of Latin lactuca lettuce, which, according to Varro, is from lac, lactis, milk: cf. French laitue. Related to Lacteal, Lactucic.
1. Any of various plants of the genus Lactuca.
2. Leaves of any of various plants of Lactuca sativa.
Annual edible plant Lactuca sativa, family Compositae, believed to have been derived from the wild species L. serriola. There are many varieties, including the cabbage lettuce, with round or loose heads, and the Cos lettuce, with long, upright heads.
Iceberg and Romaine are the two salad varieties grown especially for US supermarkets, but Boston and Redleaf are sometimes shipped to markets.