The term shareware, popularized by Bob Wallace, refers to copyrighted commercial software that is distributed without payment on a trial basis and is limited by any combination of functionality, availability, or convenience. Shareware is often offered as a download from an Internet website or as a compact disc included with a periodical such as a newspaper or magazine. The aim of shareware is to give buyers the opportunity to use the program and judge its usefulness before purchasing a licence for the full version of the software.

Shareware is usually offered as a trial version with certain features only available after the licence is purchased, or as a full version, but for a trial period. Once the trial period has passed the program will not run until a licence is purchased. Shareware is often offered without support, updates, or help menus, which only become available with the purchase of a licence. The words "free trial", "trial version" are indicative of shareware.