RPN

RPN may refer to:

==Science and technology== Real projective space (\mathbb{R}\mathrm{P}^n,), a type of topological space Reverse Polish notation, a.k.a. postfix notation, a mathematical notation Registered Parameter Number, in MIDI Recherche en Prévision Numérique, weather forecasting research service, Canada Risk priority number in failure analysis such as FMEA, taking into account the severity, probability and detection probability of a failure event