Substitutes

Substitutes are goods that can replace each other to some extent, so that a rise in the price of one good leads to a lower quantity consumed of another good, and vice versa.

Definition

According to Principles of Economics by Timothy Taylor (3rd edition),

Substitutes. Goods that can replace each other to some extent, so that a rise in the price of one good leads to a lower quantity consumed of another good, and vice versa.