ⓘ Formal


ⓘ Formal

Formal, formality, informal or informality imply the complying with, or not complying with, some set of requirements. They may refer to:


1. Dress code and events

  • Formal university, official university dinner, ball or other event
  • School formal, official school dinner, ball or other event
  • Semi-formal attire, attire for semi-formal events
  • Formal wear, attire for formal events
  • Informal attire, more controlled attire than casual but less than formal

2. Logic and mathematics

  • Formal logic, or mathematical logic
  • Informal logic, the complement, whose definition and scope is contentious
  • Informal fallacy, the complement
  • Formal fallacy, reasoning of invalid structure
  • Formal power series, a generalization of power series without requiring convergence, used in combinatorics
  • Formal cause, Aristotles intrinsic, determining cause
  • Informal mathematics, also called naïve mathematics
  • 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

3. Computer science

  • Formal specification, describes what a system should do, not how it should do it
  • Formal verification, proves correctness of a system
  • Formal methods, mathematically based techniques for the specification, development and verification of software and hardware systems

4. Linguistics

  • Formal proof, a fully rigorous proof as is possible only in a formal system
  • Formal language, comprising the symbolic "words" or "sentences" of a formal system
  • Formal grammar, a grammar describing a formal language
  • T–V distinction, involving a distinction between formal and informal words for "you"
  • Dynamic and formal equivalence word-for-word translation, especially of the Bible
  • Formal system, an abstract means of generating inferences in a formal language

5. Chemistry

  • Formal concentration, molar concentration of original chemical formula in solution
  • A compound CH 2 OR 2, named in analogy to acetals CHR 1 OR 2 historical definition and ketals CR 1 R 2 OR 2
  • Formal pronounced "form-al"
  • Dimethoxymethane CH 2 OCH 3 2) in particular, the formal derived from methanol

6. Social regulation

  • A formality, an established procedure or set of specific behaviors
  • Pro forma, for no purpose other than satisfying a formality
  • Informal activities
  • Informal settlement, or shanty town
  • Informal education, education outside of a standard school setting
  • Informal sector, the part of an economy that is not taxed, nor monitored by any form of government
  • Informal value transfer system, outside the conventional banking system
  • Informal social control, enforcing norms without resort to laws


7. Other

  • MV Formality, coaster formerly Empire Favourite owned by F T Everard & Sons, scrapped in 1962
  • Informal vote, a spoiled, void, null vote cast in an election