Deixis refers to words and phrases that require contextual information to convey meaning. These expressions, such as this, that, here, and now, depend on the speaker's perspective and the situation in which they are used. For example, saying "I will meet you here" relies on the listener knowing the specific location being referred to. There are different types of deixis, including person deixis, which indicates the speaker and listener, time deixis, which relates to when something occurs, and place deixis, which points to specific locations. Understanding deixis is essential for effective communication, as it helps clarify meaning based on context.