Copyright: "Copyright is a type of intellectual property that protects original works of authorship as soon as an author fixes the work in a tangible form of expression." (From the US Copyright Office.)
Trademark: "A trademark can be any word, phrase, symbol, design, or a combination of these things that identifies your goods or services. It’s how customers recognize you in the marketplace and distinguish you from your competitors." (From the US Trademark and Patent Office.)
Patent: "A U.S. patent gives you, the inventor, the right to “exclude others from making, using, offering for sale, or selling” an invention or “importing” it into the U.S...What is granted is not the right to make, use, offer for sale, sell or import the invention, but the right to stop others from doing so." (Excerpt from the US Trademark and Patent Office.) More about patents.
Intellectual property: "Intellectual property (IP) refers to creations of the mind, such as inventions; literary and artistic works; designs; and symbols, names and images used in commerce. IP is protected in law by, for example, patents, copyright and trademarks, which enable people to earn recognition or financial benefit from what they invent or create." (From the World Intellectual Property Organization.)
Fair use:"In its most general sense, a fair use is any copying of copyrighted material done for a limited and “transformative” purpose, such as to comment upon, criticize, or parody a copyrighted work. Such uses can be done without permission from the copyright owner. In other words, fair use is a defense against a claim of copyright infringement."
The four factors of fair use:
Purpose and character of the use, including whether the use is of a commercial nature or is for nonprofit educational purposes
Nature of the copyrighted work
Amount and substantiality of the portion used in relation to the copyrighted work as a whole
Effect of the use upon the potential market for or value of the copyrighted work
