- Supp is short for supplement, which is something added for completion or to make something more comprehensive.
An example of supp is a Smartboard lesson added to a lecture on the causes of World War II.
- (law) Abbreviation of supplement.
This is the customary abbreviation of this term as used in legal citation. See, e.g., The Bluebook: A Uniform System of Citation, Nineteenth Edition (2010), "Subdivisions", Table T16, p. 472-73.