Source : Webster's Revised Unabridged Dictionary (1913)

Margin \Mar"gin\, v. t. [imp. & p. p. {Margined}; p. pr. & vb.
   n. {Marginging}.]
   1. To furnish with a margin.

   2. To enter in the margin of a page.

Margin \Mar"gin\, n. [OE. margine, margent, L. margo, ginis. Cf.
   {March} a border, {Marge}.]
   1. A border; edge; brink; verge; as, the margin of a river or
      lake.

   2. Specifically: The part of a page at the edge left
      uncovered in writing or printing.

   3. (Com.) The difference between the cost and the selling
      price of an article.

   4. Something allowed, or reserved, for that which can not be
      foreseen or known with certainty.

   5. (Brokerage) Collateral security deposited with a broker to
      secure him from loss on contracts entered into by him on
      behalf of his principial, as in the speculative buying and
      selling of stocks, wheat, etc. --N. Biddle.

   {Margin draft} (Masonry), a smooth cut margin on the face of
      hammer-dressed ashlar, adjacent to the joints.

   {Margin of a course} (Arch.), that part of a course, as of
      slates or shingles, which is not covered by the course
      immediately above it. See 2d {Gauge}.

   Syn: Border; brink; verge; brim; rim.

Source : WordNet®

margin
     n 1: the boundary line or the area immediately inside the
          boundary [syn: {border}, {perimeter}]
     2: a permissible difference; allowing some freedom to move
        within limits [syn: {allowance}, {leeway}, {tolerance}]
     3: the amount of collateral a customer deposits with a broker
        when borrowing from the broker to buy securities [syn: {security
        deposit}]
     4: (finance) the net sales minus the cost of goods and services
        sold [syn: {gross profit}, {gross profit margin}]
     5: the blank space that surrounds the text on a page
     6: a strip near the boundary of an object; "he jotted a note on
        the margin of the page" [syn: {edge}]