The term "clean room" is borrowed from the ultra-clean, filtered-air rooms in which silicon chips are made. As originally used with respect to software, the term refers to a way of creating of software that can prove to a court that no copying occured of protectable elements of the original program.

Such a clean room is used under several different circumstances which include:

• The development of a new program designed to compete with or to interoperate with an original program (see Sega Enterprises v. Accolade).
• To remediate a situation in which there has been an allegation of improper similarities (see such cases as Computer Associates v. Altai or Nintendo v. Atari).

The essence of clean room software development in this legal sense is:

• The establishment of development procedures that will create a meticulous audit trail showing every aspect and stage of the development process.
• The creation of design documentation that records the functional requirements of the intended program that is demonstrably devoid of any protectable elements.

Three different groups of people are required for a clean room development:

• The technicians in the clean room team, uncontaminated by the original proprietary software.
• The technicians outside the clean room, who study the original proprietary software and prepare the functional specification for the clean room team.
• The supervisor(s) of the clean room, who are interposed between the team inside and outside the clean room. Such supervisors normally consist of both legal and technical personnel.