The Collaborative International Dictionary of English v.0.48:

Melilot \Mel"i*lot\ (-l[o^]t), n. [F. m['e]lilot, L. melilotus,
   fr. Gr. ?, ?, a kind of clover containing honey; me`li honey
   + ? lotus.] (Bot.)
   Any species of Melilotus, a genus of leguminous herbs
   having a vanillalike odor; sweet clover; hart's clover. The
   blue melilot (Melilotus caerulea) is used in Switzerland to
   give color and flavor to sapsago cheese.
   [1913 Webster]

WordNet (r) 3.0 (2006):

melilot
    n 1: erect annual or biennial plant grown extensively especially
         for hay and soil improvement [syn: melilotus, melilot,
         sweet clover]