The Collaborative International Dictionary of English v.0.48:

Glean \Glean\, v. t. [imp. & p. p. Gleaned; p. pr. & vb. n.
   Gleaning.] [OE. glenen, OF. glener, glaner, F. glaner, fr.
   LL. glenare; cf. W. glan clean, glanh?u to clean, purify, or
   AS. gelm, gilm, a hand?ul.]
   [1913 Webster]
   1. To gather after a reaper; to collect in scattered or
      fragmentary parcels, as the grain left by a reaper, or
      grapes left after the gathering.
      [1913 Webster]

            To glean the broken ears after the man
            That the main harvest reaps.          --Shak.
      [1913 Webster]

   2. To gather from (a field or vineyard) what is left.
      [1913 Webster]

   3. To collect with patient and minute labor; to pick out; to
      obtain.
      [1913 Webster]

            Content to glean what we can from . . . experiments.
                                                  --Locke.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Glean \Glean\, v. i.
   1. To gather stalks or ears of grain left by reapers.
      [1913 Webster]

            And she went, and came, and gleaned in the field
            after the reapers.                    --Ruth ii. 3.
      [1913 Webster]

   2. To pick up or gather anything by degrees.
      [1913 Webster]

            Piecemeal they this acre first, then that;
            Glean on, and gather up the whole estate. --Pope.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Glean \Glean\, n.
   A collection made by gleaning.
   [1913 Webster]

         The gleans of yellow thyme distend his thighs.
                                                  --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Glean \Glean\, n.
   Cleaning; afterbirth. [Obs.] --Holland.
   [1913 Webster]

WordNet (r) 3.0 (2006):

glean
    v 1: gather, as of natural products; "harvest the grapes" [syn:
         reap, harvest, glean]

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "glean":
   accumulate, amass, ascertain, assemble, bring in, bring together,
   choose out, collect, conclude, crop, crop herbs, cull, cut,
   decide between, deduce, derive, dig, dig up, draw a conclusion,
   draw an inference, excerpt, extract, fetch, find, garner, gather,
   gather in, get in, get together, grabble, grub, grub up, handpick,
   harvest, hay, induce, infer, learn, make a selection, mow, nut,
   pick, pick out, pick up, pluck, rake up, reap, reap and carry,
   reason, reason that, round up, scare up, scrape together,
   scrape up, select, sift, single out, take as proved, take up,
   winnow



Easton's 1897 Bible Dictionary:

Glean
   The corners of fields were not to be reaped, and the sheaf
   accidentally left behind was not to be fetched away, according
   to the law of Moses (Lev. 19:9; 23:22; Deut. 24:21). They were
   to be left for the poor to glean. Similar laws were given
   regarding vineyards and oliveyards. (Comp. Ruth 2:2.)