The Collaborative International Dictionary of English v.0.48:

Milt \Milt\, n. [AS. milte; akin to D. milt, G. milz, OHG.
   milzi, Icel. milti, Dan. milt, Sw. mj[aum]lte, and prob. to
   E. malt, melt. [root]108. See Malt the grain.] (Anat.)
   The spleen.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Milt \Milt\, n. [Akin to Dan. melk, Sw. mj["o]lke, G. milch, and
   E. milk. See Milk.] (Zool.)
   (a) The spermatic fluid of fishes.
   (b) The testes, or spermaries, of fishes when filled with
       spermatozoa.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Milt \Milt\, v. t.
   To impregnate (the roe of a fish) with milt.
   [1913 Webster]

WordNet (r) 3.0 (2006):

milt
    n 1: fish sperm or sperm-filled reproductive gland; having a
         creamy texture [syn: milt, soft roe]
    2: seminal fluid produced by male fish