The Collaborative International Dictionary of English v.0.48:

Gob \Gob\ (g[o^]b), n. [Cf. Goaf.] (Mining)
   Same as Goaf.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gob \Gob\, n. [OF. gob morsel; cf. F. gobe, gobbe, a poisoned
   morsel, poison ball, gobet a piece swallowed, gober to
   swallow greedily and without tasting; cf. Gael. & Ir. gob
   mouth, snout, W. gwp a bird's head and neck. Cf. Gobble,
   Job, n.]
   1. A little mass or collection; a small quantity; a mouthful.
      [Low] --L'Estrange.
      [1913 Webster]

   2. The mouth. [Prov. Eng.or Low] --Wright.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gob \Gob\ (g[o^]b), n.
   Same as sailor. [Colloq.]
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Goaf \Goaf\; n.; pl. Goafsor Goaves. [Cf. 1st Gob.]
   (Mining)
   That part of a mine from which the mineral has been partially
   or wholly removed; the waste left in old workings; -- called
   also gob .
   [1913 Webster]

   To work the goaf or To work the gob, to remove the
      pillars of mineral matter previously left to support the
      roof, and replace them with props. --Ure.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gob
    n 1: a man who serves as a sailor [syn: mariner, seaman,
         tar, Jack-tar, Jack, old salt, seafarer, gob,
         sea dog]
    2: a lump of slimy stuff; "a gob of phlegm"
    3: informal terms for the mouth [syn: trap, cakehole,
       hole, maw, yap, gob]