Ceteris paribus is an expression derived from Latin and commonly used in economics. It means "all else being equal". Changes to economic variables cannot be examined in real life independently, as related variables are changing constantly. Ceteris paribus refers to this hypothetical vacuum. For example, we can say that "ceteris paribus, people buy less apples when the price of apples goes up", meaning that the statement is true, after accounting for all other factors, such as the price of other goods, people's income, availability of apples, etc.