Type

Type is a broad term used across disciplines to denote a category of objects or values that share defining properties. The notion helps organize and constrain what counts as admissible, and it can apply to language, mathematics, and technology.

In typography, type refers to letterforms used in printing and digital text. It encompasses typefaces and fonts, their design, spacing, and readability. Historically, movable metal type gave rise to printing; today digital fonts are used with varied metrics and licensing.

In computing, a type classifies a value to define what operations are valid and how much storage it requires. Common types include integers, floating-point numbers, booleans, strings, and dates. Typing can be static or dynamic, strong or weak, and may be inferred.

A type system is a formal framework in programming languages that enforces rules about how values of different types interact. It helps prevent errors, supports abstraction through generics and polymorphism, and, in some languages, enables advanced features such as dependent or expressive typing.

In logic and mathematics, type theory assigns levels to objects to avoid paradoxes and to formalize computation. Simple type theory, developed in the early 20th century, underpins many proof systems and interactive theorem provers, illustrating the unifying role of type across disciplines.