Philosophical term for an indivisible, fundamental unit, especially in Leibniz's metaphysics. Also used in other contexts such as biology or computer science, but philosophy is the focus here.
See also: モナド
In Leibniz's philosophy, monads are considered indivisible substances.
This concept is also related to monadology in biology.
From 単 (simple, single) and 子 (small thing, particle), likely a Meiji-era coinage as a translation of the Western philosophical term 'monad'. The exact derivation is uncertain.