The document defines and provides examples of metonymy and synecdoche. Metonymy is when a word or phrase is substituted for a similar or related concept, such as referring to a crown to represent the monarchy. Synecdoche is when a part represents the whole or vice versa, like using "wheels" to refer to a car. Examples include referring to "John Hancock" to represent the person and using "screen door" in a song to represent summer.