Deixis

Etymology

From Greek "deixis" (a pointing, reference), from "deiknynai" (to show, point out). The related adjective is "deictic." A term of art in linguistics and philosophy of language.

noun · /DYKE-sis/
The way certain words point to meaning only through the context in which they are said.
What it names
Why "meet me here tomorrow" is useless on a stray note — a handle for the words ("I," "now," "this," "there") whose sense collapses without a speaker, time, and place.
Example
A message reading "he’ll be back here in an hour" is pure deixis — meaningless once you no longer know who, where, or when it was written.
Related idea
Contrast the linguistic sense of anaphora — a word pointing back to something earlier in the text itself — with deixis, which points outward to the real-world situation.