Deixis refers to words and phrases whose meaning depends on the context of the utterance. There are three main types of deixis: person deixis refers to pronouns like "I" and "you"; spatial deixis indicates locations like "here" and "there"; and temporal deixis refers to times like "now" and "then". Deixis allows speakers to indicate people, places, and times from their own perspective through the use of proximal terms that are near the speaker spatially or temporally, and distal terms that are farther away. Understanding deixis requires understanding not just the literal meaning of words but how their meaning shifts based on who is speaking, where, when, and other contextual factors.