Nonproprietary is a term used to describe something that is not privately owned or patented by an individual or a company. There are several synonyms for the word nonproprietary that can be used interchangeably depending on the context of its usage. These synonyms include open-source, public, available, unpatented, free, accessible, common, generic, and unrestricted. Open-source is used in relation to software, public is commonly used for land and government resources, while free is used for products or services that are offered without payment. Each of these synonyms has a different connotation and may be suitable for different situations.