[1] : The Collaborative International Dictionary of English v.0.48

lettuce \let"tuce\ le^t"ti^s, n. oe. letuce, prob.
   through old french from some late latin derivative of l.
   lactuca lettuce, which, according to varro, is fr. lac,
   lactis, milk, on account of the milky white juice which flows
   from it when it is cut: cf. f. laitue. cf. lacteal,
   lactucic.
   1. bot. a composite plant of the genus lactuca lactuca
      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 lactuca canadensis.
      1913 webster

   2. united states currency; dollar bills; greenbacks. slang
      pjc

   hare's lettuce, lamb's lettuce. see under hare, and
      lamb.

   lettuce opium. see lactucarium.

   sea lettuce, certain papery green seaweeds of the genus
      ulva.
      1913 webster
see also:
lacteal lactucic lactuca lactuca sativa lactuca canadensis hare's lettuce 
lamb's lettuce hare lamb lettuce opium lactucarium 
sea lettuce ulva 

Lettuce >> L Words
Lettuce, definition of term: Lettuce
lettuce_pag1.html

Opium >> O Words
Opium, definition of term: Opium
opium_pag1.html

Opium Poppy >> O Words
Opium Poppy, definition of term: Opium Poppy
opium+poppy_pag1.html

Sea Lettuce >> S Words
Sea Lettuce, definition of term: Sea Lettuce
sea+lettuce_pag1.html