Monadologia Physica by Immanuel Kant

Monism, the concept of "one essence" in the metaphysical and theological theory

Windows PowerShell, a command line interface for Microsoft Windows code-named "Monad"

Monads in functional programming, type constructors that are used in functional programming languages to capture various notions of computation

Monadology, a book of philosophy by Gottfried Leibniz in which monads are a basic unit of perceptual reality

The Cup or Monad, a text in the Corpus Hermetica

Monad (category theory), a type of functor in category theory

John Monad, title character of the television series John from Cincinnati

Xmonad, a window manager for the X Window System

Monadic predicate calculus is a form of logic based on unary operators

Monad (Gnosticism), the most primal aspect of God in Gnosticism

Monad (symbol), a term used by ancient philosophers Pythagoras, Parmenides, Xenophanes, Plato, Aristotle, and Plotinus as a term for God or the first being, or the totality of all beings

Monad (music), a single note, in contradistinction to a dyad, triad, tetrad, etc

Monad (Technocracy), the symbol of Technocracy Incorporated and the Technocratic movement of North America