"Magic" can used as a descriptor, for example, when referring to a "magic show" or "magic trick." A person who performs magic is a magician.
"Magic” is often used in advertising, for example, as in the overused "works like magic," which has been applied to cleaning products and just about anything that's pitched through late night infomercials. "Magic" is also often used in themes, for example, "The Magic of Volunteerism" or "The Magic of Higher Math."
For those that believe in paranormal phenomena, there are branches such as "dark magic."