Most references state that the Greek Muses number nine, a few of whose names are part of modern English—terpsichore, the art of dance; and, calliope, a steam organ. These nine best-known Muses are connected with Hellenic Greek mythology of Mt. Olympus and the Olympian deities—these are sometimes called the Younger Muses.
One must do further reading to learn that before the muses numbered nine, they numbered three, and before that, there was one. The little-known three Elder Muses have their own sacred mountain, Mt. Helicon, and their three attributes consist of voice, memory, and meditation. Those three attributes enable performance: of poetry, of theater, of music.
Whatever their number, Muses inspire.
When I was a music & theater major, that latter quality of meditation we called “concentration”—the focused, practiced production of sound, emotion, intention that seized and moved our audiences. And when I was brought in to the Wicca, I found that the same sort of “concentration” enables our magic. As the Brits say, “Snap!”