The Collaborative International Dictionary of English v.0.48:

Erasure \E*ra"sure\ (?; 135), n. [From Erase.]
   1. The act of erasing; a scratching out; obliteration.
      [1913 Webster]

   2. the place where something has been erased.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

erasure
    n 1: a correction made by erasing; "there were many erasures in
         the typescript"
    2: a surface area where something has been erased; "another word
       had been written over the erasure"
    3: deletion by an act of expunging or erasing [syn:
       expunction, expunging, erasure]

Moby Thesaurus II by Grady Ward, 1.0:

80 Moby Thesaurus words for "erasure":
   abbreviation, ablation, abrasion, abrasive, abridgment, attrition,
   blackout, blocking, blot, blotting, blotting out, blue-penciling,
   bowdlerization, buffing, burnishing, cancel, cancellation,
   censoring, censorship, chafe, chafing, deletion, dematerialization,
   departure, detrition, disappearance, disappearing, dispersion,
   dissipation, dissolution, dissolving, dressing, eclipse, editing,
   effacement, elimination, erosion, evanescence, evaporation,
   expunction, expurgation, extinction, fadeaway, fadeout, fading,
   filing, fretting, galling, going, grazing, grinding, limation,
   melting, obliteration, occultation, omission, passing, polishing,
   rasping, rubbing away, sandblasting, sanding, scouring, scrape,
   scraping, scratch, scratching, scrub, scrubbing, scuff, shining,
   smoothing, striking, vanishing, vanishing point, washing out, wear,
   wearing away, wipe, wiping out



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ERASURE, contracts, evidence. The obliteration of a writing; it will render
it void or not under the same circumstances as an interlineation. (q.v.)
Vide 5 Pet. S. C. R. 560; 11 Co. 88; 4 Cruise, Dig. 368; 13 Vin. Ab. 41;
Fitzg. 207; 5 Bing. R. 183; 3 C. & P. 65; 2 Wend. R. 555; 11 Conn. R. 531; 5
M. R. 190; 2 L. R. 291 3 L. R. 56; 4 L. R. 270.
     2. Erasures and interlineations are presumed to have been made after
the execution of a deed, unless the contrary be proved. 1 Dall. 67; 1 Pet.
169; 4 Bin. 1; 10 Serg. & R. 64, 170, 419; 16 Serg. & R. 44.