A patent is a time-limited intellectual property right granted by a government office which provides the patent owner(s) exclusive rights on the patented invention (manufacture, use, sale, import). It does not, however, guarantee that the owner can use or exploit it since access to other patented inventions may be necessary for such use or exploitation (source CERN IP policy). Patents can be used to protect products, processes, or use of a product. A patent should describe the technical problem to be solved, how the invention solves it, and how this offered solution differs from the known prior art.

"Public disclosure" must be distinguished from what is called technology/invention disclosure in the knowledge/technology transfer process. The former impacts the patentability of an invention, while the latter is one step towards dissemination through knowledge/technology transfer.

A disclosure is considered public even if made to a restricted group of persons or single person. Publications in books and technical journals, poster sessions, slides, lectures, seminars, letters, even conversations can count as a bar to patentability--depending on the country. This is not the case if the information is conveyed under confidentiality obligations however. It is also not the case if made among colleagues.

Copyright is a form of protection which comes into existence automatically with the creation of the work. It protects literary and artistic works, in a broad sense, which are fixed in a tangible medium of expression. Copyright protects the expression of ideas, not the ideas themselves, and gives their authors exclusive rights to reproduce the copyrighted material. Copyrighted works include computer programs. (Source:  CERN IP policy)

A Trade Secret is information which is not generally known (a formula, manufacturing process, method of doing business, or technical know-how) that gives its holder a competitive advantage. 

The basic principle underlying Open Source Software is that the software source code is made available, allowing others to modify the software. But this is only one aspect. An Open Source licence means license conditions that are compatible with the principles defined by the Open Source Initiative, for instance free redistribution, or no discrimination against persons, groups, or fields of endeavour (for more information see http://www.opensource.org/osd.html).