hole
     n 1: an opening into or through something
     2: an opening deliberately made in or through something
     3: one playing period (from tee to green) on a golf course; "he
        played 18 holes" [syn: {golf hole}]
     4: an unoccupied space
     5: a depression hollowed out of solid matter [syn: {hollow}]
     6: a fault; "he shot holes in my argument"
     7: informal terms for a difficult situation; "he got into a
        terrible fix"; "he made a muddle of his marriage" [syn: {fix},
         {jam}, {mess}, {muddle}, {pickle}, {kettle of fish}]
     8: informal terms for the mouth [syn: {trap}, {cakehole}, {maw},
         {yap}, {gob}]
     v 1: hit the ball into the hole [syn: {hole out}]
     2: make holes in
Source: WordNet® 2.0

hole n. A region in an otherwise {flat} entity which is not actually
   present. For example, some Unix filesystems can store large files with
   holes so that unused regions of the file are never actually stored on
   disk. (In techspeak, these are referred to as `sparse' files.) As
   another example, the region of memory in IBM PCs reserved for
   memory-mapped I/O devices which may not actually be present is called
   `the I/O hole', since memory-management systems must skip over this area
   when filling user requests for memory.


Source: The Jargon File