2. Noun. (computing) Any program which compares two files or sets of files and outputs a description of the differences between them. ¹
3. Noun. (computing) The output of a diff program. A diff file. ¹
4. Noun. (medicine) (abbreviation of differential): differential of types of white blood cell in a complete blood count. ¹
5. Noun. (slang) (abbreviation of difficult) ¹
6. Noun. (context: rock climbing) A difficult route. ¹
7. Verb. (transitive computing) To run a diff program on (files or items). ¹
8. Verb. (transitive computing) To produce a description of changes made to a collection of files. To produce a patch file. ¹
9. Verb. (transitive computing) To compare two files or other objects, manually or otherwise. ¹
10. Proper noun. (computing) A program, historically part of the Unix operating system, which compares two files or sets of files and outputs a description of the differences between them. ¹
¹ Source: wiktionary.com
Definition of Diff
1. a difference [n -S]