indexical (adj.)

(1) A term used by some LINGUISTS to refer to features of speech or writing which reveal the personal (biological, psychological or social) characteristics of a LANGUAGE user, as in VOICE QUALITY or handwriting. More generally, the term may be used to refer to the membership-identifying characteristics of a group, such as regional, social or occupational indices.

(2) The philosophical use of this term (either alone, or in the phrase indexical expression) is sometimes encountered in LINGUISTICS to refer to those features of language which refer directly to characteristics of the SITUATION within which an UTTERANCE takes place; their meaning is thus relative to that situation. Linguists more regularly refer to these features as DEICTIC features. Pure indexical is sometimes used for those indexical EXPRESSIONS whose REFERENCE is fixed automatically by the time, place, etc. of utterance, such as yesterday; it contrasts with DEMONSTRATIVE.