lettuce (n.)

garden herb extensively cultivated for use as a salad, late 13c., letuse, probably somehow from Old French laitues, plural of laitue "lettuce" (cognate with Spanish lechuga, Italian lattuga), from Latin lactuca "lettuce," from lac (genitive lactis) "milk" (from PIE root *g(a)lag- "milk"); so called for the milky juice of the plant. Old English had borrowed the Latin word as lactuce.