A more thorough explanation:

A combination in restraint of trade is an agreement between two or more individuals or entities that is intended to increase prices, decrease output, or establish a monopoly. This type of agreement is also known as a "combine."

For example, if two competing companies agree to fix their prices at a certain level, this would be considered a combination in restraint of trade. Similarly, if several companies in the same industry agree to limit their production in order to keep prices high, this would also be a combination in restraint of trade.

These types of agreements are illegal under antitrust laws, which are designed to promote competition and prevent monopolies. By limiting competition, combinations in restraint of trade can harm consumers by driving up prices and reducing choices.