The Collaborative International Dictionary of English v.0.48:

Lump \Lump\ (l[u^]mp), n. [Cf. OD. lompe piece, mass. Cf.
   Lunch.]
   1. A small mass of matter of irregular shape; an irregular or
      shapeless mass; as, a lump of coal; a lump of iron ore. "
      A lump of cheese." --Piers Plowman. " This lump of clay."
      --Shak.
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   2. A mass or aggregation of things.
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   3. (Firearms) A projection beneath the breech end of a gun
      barrel.
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   In the lump,

   In a lump, the whole together; in gross.
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            They may buy them in the lump.        --Addison.

   Lump coal, coal in large lumps; -- the largest size brought
      from the mine.

   Lump sum,
      (a) a gross sum without a specification of items; as, to
          award a lump sum in satisfaction of all claims and
          damages.
      (b) a single sum paid once in satisfaction of a claim, as
          contrasted with the alternate choice of several
          payments over a period of time; -- sometimes allowed,
          e.g., as an alternative to periodical pension payments
          for a lifetime.
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The Collaborative International Dictionary of English v.0.48:

Lump \Lump\, v. i. [imp. & p. p. Lumped; p. pr. & vb. n.
   Lumping.]
   1. To throw into a mass; to unite in a body or sum without
      distinction of particulars.
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            The expenses ought to be lumped together. --Ayliffe.
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   2. To take in the gross; to speak of collectively.
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            Not forgetting all others, . . . whom for brevity,
            but out of no resentment to you, I lump all
            together.                             --Sterne.
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   3. To get along with as one can, although displeased; as, if
      he doesn't like it, he can lump it. [Low]
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WordNet (r) 3.0 (2006):

lump
    n 1: a compact mass; "a ball of mud caught him on the shoulder"
         [syn: ball, clod, glob, lump, clump, chunk]
    2: an abnormal protuberance or localized enlargement [syn:
       swelling, puffiness, lump]
    3: an awkward stupid person [syn: lout, clod, stumblebum,
       goon, oaf, lubber, lummox, lump, gawk]
    4: a large piece of something without definite shape; "a hunk of
       bread"; "a lump of coal" [syn: hunk, lump]
    v 1: put together indiscriminately; "lump together all the
         applicants" [syn: lump, chunk]
    2: group or chunk together in a certain order or place side by
       side [syn: collocate, lump, chunk]