Multiplicity
Multiplicity may refer to:

In popular culture
Multiplicity (subculture), an online subculture of people having or using multiple personalities.

In science and the humanities
Multiplicity (chemistry), multiplicity in quantum chemistry is a function of angular spin momentum
Multiplicity (mathematics), the number of times an element is repeated in a multiset
Multiplicity (philosophy), a philosophical concept
Multiplicity (psychology), psychological phenomenon where a body features multiple distinct or overlapping consciousnesses
Multiplicity (software), a software application which allows a user to control two or more computers from one mouse and keyboard
Multiplicity, a type of relationship in class diagrams for Unified Modeling Language used in software engineering
Multiplicity (statistical mechanics), the number of  microstates corresponding to a particular macrostate in a thermodynamic system, symbolized by the Greek letter Ω
Statistical multiplicity, also known as the problem of multiple comparisons.

In the arts
Multiplicity (film), a 1996 comedy film starring Michael Keaton
Multiplicity (album), 2005 studio album by Dave Weckl