Type has historically had the following uses:
- In computing, the datatype (sometimes called simply type) of an object depends on its classifier. In object-oriented programming, it became useful to distinguish an abstract data type from an implemented datatype.
- In the decades of the 1900s and 1910s, in philosophy, Bertrand Russell used his theory of types to further discuss the mapping of mathematics to logic. See Principia Mathematica
- In the development of printing, type was used for the metal forms of the letters used in typesetting. See, for example, typewriter.
