Margin

1. n. 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.
2. n. A border; edge; brink; verge; as, the margin of a river or lake.
3. n. Specifically: The part of a page at the edge left uncovered in writing or printing.
4. n. The difference between the cost and the selling price of an article.
5. n. Something allowed, or reserved, for that which can not be foreseen or known with certainty.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.