Source : Webster's Revised Unabridged Dictionary (1913)

Luffa \Luf"fa\, n. [NL., fr. Ar. l[=u]fah.] (Bot.)
   (a) A small genus of tropical cucurbitaceous plants having
       white flowers, the staminate borne in racemes, and large
       fruits with a dry fibrous pericarp. The fruit of several
       species and the species themselves, esp. {L.
       [AE]gyptiaca}, are called dishcloth gourds.
   (b) Any plant of this genus, or its fruit.
   (c) The fibrous skeleton of the fruit, used as a sponge and
       in the manufacture of caps and women's hats; -- written
       also {loofah}.

Source : WordNet®

luffa
     n 1: the dried fibrous part of the fruit of a plant of the genus
          Luffa; used as a washing sponge or strainer [syn: {loofa},
           {loofah}, {loufah sponge}]
     2: any of several tropical annual climbers having large yellow
        flowers and edible young fruits; grown commercially for
        the mature fruit's dried fibrous interior that is used as
        a sponge [syn: {dishcloth gourd}, {sponge gourd}, {rag
        gourd}, {strainer vine}]