From Wikipedia, the free encyclopedia

The term formal has a number of uses, including:

Contents 1 General 2 Social 3 Philosophical 4 Mathematics 4.1 Logic and Language 5 Computer science 6 Linguistic 7 Chemical 8 See also

• relating to formality
• opposite of informal

• Formal occasion
  • Formal attire worn on such occasions
  • Formals are particular meals at some British universities
  • In Australian or British English, a "formal" is the equivalent of the American prom dance.
  • In American English, a "formal" is organized by a college or university organization, typically but not always a fraternity or sorority.
• Informal occasion (included as Informal redirect here); see Dress code (Western) for the distinctions between Formal, Semi-formal, and Informal
  • Informal attire (not to be confused with Casual -- see Dress code (Western))

• relating to form, i.e. appearance rather than essence.
  • relating to Formalism, i.e. emphasis on form over content or meaning.
• formal logic logical argument based only on the form and not on the meaning.
• Formal cause, Aristotle's intrinsic, determining cause.

• formal power series, a generalization of power series without requiring convergence, used in combinatorics;
• formal calculation, a calculation which is systematic, but without a rigorous justification;
• formal set theory as opposed to naive set theory;
• formal derivative, an operation on elements of a polynomial ring which mimics the form of the derivative from calculus.

• formal system, an abstract means of generating inferences in a formal language;
  • formal language, comprising the symbolic "words" or "sentences" of a formal system;
    • formal grammar, a grammar describing a formal language;
  • formal proof, a fully rigorous proof as is possible only in a formal system.

• formal methods in computer science, including:
  • formal specification describes what a system should do, not how it should do it
  • formal verification proves correctness of a system

See also the Language section of Mathematics, above

• Formal equivalence word-for-word translation (especially of the Bible)

See also the Language section of Mathematics, above

• A unit of concentration
• short or prefix form for formalin
• short or prefix form for formaldehyde
• synonym for dimethoxymethane

• Informal economy