diff

n. difference; (Computers) program that makes a comparison of two files and produces a report of the differences between them

In computing, diff is a file comparison utility that outputs the differences between two files. The program displays the changes made per line for text files. Modern implementations also support binary files. The output is called a diff or more commonly a patch since the output can be applied with the program patch. The output of similar file comparison utilities are also called a "diff". Like the use of the word "grep" for describing the act of searching, the word diff is used in jargon as a verb for calculating any difference.
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Difference is the contrary of equality, in particular of objects. Differences can only be stated on the basis of a comparison or categorization. Since a complete comparison of objects or things is seldom possible in practice, only relevant or defining attributes are used for stating equality or difference. Similar objects are only different with respect to attributes of minor discriminative value.
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/dif/ 1. A change listing, especially giving differences between (and additions to) different versions of a piece of source code or documentation (the term is often used in the plural "diffs"). "Send me your diffs for the Jargon File!"
Compare vdiff.
2. Specifically, such a listing produced by the diff Unix command, especially when used as input to the patch utility (which actually performs the modifications). This is a common method of distributing patches and source updates.
3. To compare (whether or not by use of automated tools on machine-readable files).
See also vdiff, mod.
[Jargon File]
(1995-02-10)

Short version of Euro-rate differential, which is a Chicago Mercantile Exchange Futures  contract that is founded on the interest rate spread between the U.S. dollar and the British pound, the German mark, or the Japanese yen.