From Mises Wiki, the global repository of classical-liberal thought
Ceteris paribus is a Latin phrase, literally translated as "with other things the same," or "all other things being equal or held constant." It is commonly used in economics, since economic examples typically involve the interaction of many variables, such as supply and demand. Ceteris paribus, an increase in the price of a substitute for corn will tend to increase the price of corn as well, for instance. It is necessary to make that disclaimer because if the market is suddenly flooded with corn at the same time that the corn substitute goes up in price, the generalization might not apply to that situation.