The English adjective free is commonly used in one of two meanings: "at no monetary cost" (gratis) and "with little or no restriction" (libre). This ambiguity of free can cause issues where the distinction is important, as it often is in dealing with laws concerning the use of information, such as copyright and patents.

The terms gratis and libre may be used to categorise intellectual property, particularly computer programs, according to the licenses and legal restrictions that cover them, in the free software and open source communities, as well as the broader free culture movement. For example, they are used to distinguish freeware (software gratis) from free software (software libre).

Richard Stallman summarised the difference in a slogan: "Think free as in free speech, not free beer."