This document discusses key concepts in semantics including referring expressions, predicators, and predicates. It defines referring expressions as parts of a sentence that refer to something and the remainder as the other words. The predicator is the single word or group of words in the remainder that contributes most to the sentence's meaning. Predicates are any words that can function as a predicator. Predicates can be one, two, or three-place depending on the number of arguments they require. Grammatical and semantic analyses of sentences differ in how they break down elements. Language can be used to discuss imaginary worlds through fiction.