indexical

adj

1. Of, pertaining to, or like, an index; having the form of an index.
2. Having or imparting a meaning, or signifying a referent, that changes according to context.

   “In order that they might represent the worlds of experience and imagination, such symbols have to be put together with ‘indexical’ signs, as Peirce termed them, such as articles (the, some), demonstratives (this, those), tense-inflections (walk-s, walk-ed), moods (may/might walk, shall/should walk) etc.”

noun

1. An indexical term.

   “So even with indexicals, there is a Sinn for every meaning.”