प्रमाण या सिद्धि (Proof) निम्नलिखित अर्थों में प्रयुक्त हो सकता है:

• ऐसी दलील जो परिपूर्ण (rigorous) एवं वाध्यकारी हो
  • प्रमाण
  • औपचारिक प्रमाण
  • गणितीय प्रमाण
  • सिद्धि सिद्धान्त, a branch of mathematical logic that represents proofs as formal mathematical objects
  • तर्कपूर्ण कथन
  • कानूनी साक्ष्य (Evidence)

• विभिन्न प्रकार के जाँच, परीक्षण एवं मापन आदि
  • Proofing, the process by which a yeast-leavened dough rises, also called “proving”
  • Proofreading
  • Artist's proof, a single print taken during the printmaking process
  • Proof coinage, a coin made as an example of a particular strike
  • Proof test, for a firearm
  • Homeopathic proving, testing a substance's effect on the body
  • Galley proof, a preliminary version of a publication
  • Proof (alcohol), a measure of an alcoholic drink’s strength