The Collaborative International Dictionary of English v.0.48:

Dig \Dig\, v. i.
   1. To work with a spade or other like implement; to do
      servile work; to delve.
      [1913 Webster]

            Dig for it more than for hid treasures. --Job iii.
                                                  21.
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            I can not dig; to beg I am ashamed.   --Luke xvi. 3.
      [1913 Webster]

   2. (Mining) To take ore from its bed, in distinction from
      making excavations in search of ore.
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   3. To work hard or drudge; specif. (U. S.): To study
      ploddingly and laboriously. [Colloq.]
      [Webster 1913 Suppl.]

            Peter dug at his books all the harder. --Paul L.
                                                  Ford.
      [Webster 1913 Suppl.]

   4. (Mach.) Of a tool: To cut deeply into the work because ill
      set, held at a wrong angle, or the like, as when a lathe
      tool is set too low and so sprung into the work.

   To dig out, to depart; to leave, esp. hastily; decamp.
      [Slang, U. S.]
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Dig \Dig\ (d[i^]g), v. t. [imp. & p. p. Dug (d[u^]g) or
   Digged (d[i^]gd); p. pr. & vb. n. Digging. -- Digged is
   archaic.] [OE. diggen, perh. the same word as diken, dichen
   (see Dike, Ditch); cf. Dan. dige to dig, dige a ditch; or
   (?) akin to E. 1st dag. [root]67.]
   1. To turn up, or delve in, (earth) with a spade or a hoe; to
      open, loosen, or break up (the soil) with a spade, or
      other sharp instrument; to pierce, open, or loosen, as if
      with a spade.
      [1913 Webster]

            Be first to dig the ground.           --Dryden.
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   2. To get by digging; as, to dig potatoes, or gold.
      [1913 Webster]

   3. To hollow out, as a well; to form, as a ditch, by removing
      earth; to excavate; as, to dig a ditch or a well.
      [1913 Webster]

   4. To thrust; to poke. [Colloq.]
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            You should have seen children . . . dig and push
            their mothers under the sides, saying thus to them:
            Look, mother, how great a lubber doth yet wear
            pearls.                               --Robynson
                                                  (More's
                                                  Utopia).
      [1913 Webster]

   5. To like; enjoy; admire. The whole class digs Pearl Jam.
      [Colloq.]
      [PJC]

   To dig down, to undermine and cause to fall by digging; as,
      to dig down a wall.

   To dig from, To dig out of, To dig out, To dig up, to
      get out or obtain by digging; as, to dig coal from or out
      of a mine; to dig out fossils; to dig up a tree. The
      preposition is often omitted; as, the men are digging
      coal, digging iron ore, digging potatoes.

   To dig in,
      (a) to cover by digging; as, to dig in manure.
      (b) To entrench oneself so as to give stronger resistance;
          -- used of warfare or negotiating situations.

   to dig in one's heels To offer stubborn resistance.
      [1913 Webster +PJC]