1. In sociolinguistics and stylistics, variations of linguistic style or tone in relation to conventions regarding appropriateness to the social context of use: in particular in relation to the situation, setting (public or private), communicative genre, audience size, and communicative relationships (including degree of acquaintance). Martin Joos (1907–78), an American linguist, identified five degrees of formality in language: intimate, casual, consultative, formal, and frozen. These are sometimes referred to as registers. Compare elaborated code; restricted code.
2. In communication theory, an aspect of modes of address: relative formality or social distance being one of the ways in which these differ. Using Edward T. Hall's terms for ‘zones’ in proxemics, a distinction can be made between intimate, personal, social and public (or impersonal) modes of address. In camerawork this is reflected in shot sizes—*close-ups signifying intimate or personal modes, medium shots a social mode, and long shots an impersonal mode.
3. A dimension of connotation in relation to communicative choices, where some forms may be subjectively evaluated as relatively formal or casual: as in choosing Times or Lucida Handwriting (fonts), word-processing or handwriting, post or email. Such choices may be interpreted as implying either a formal or a casual communicative relationship which may be evaluated in terms of appropriateness.