■ noun
1》 a cultivated plant of the daisy family, with edible leaves that are eaten in salads. [ Lactuca sativa .]
2》 used in names of other plants with edible green leaves, e.g. lamb's ~ .
Origin
ME: from OFr. letues , laitues , plural of laitue , from L. lactuca , from lac , lact- 'milk' (because of its milky juice).