This document discusses semantic change, which refers to how the meanings of words evolve over time. It provides examples of different types of semantic change, including narrowing, broadening, amelioration, and pejoration. Narrowing involves a word becoming more specific in meaning, like "hound" changing to only refer to hunting dogs. Broadening means a word is used in more contexts and becomes more general, such as "business" expanding from "being busy" to any type of work. Amelioration occurs when a word acquires a more positive connotation, and pejoration is when a word's meaning deteriorates to be more negative. The document examines how factors like culture and technology can influence semantic shifts over periods