Yes, Merlin, as in King Arthur's Merlin, as in Walt Disney's Fantasia; see disembodied entity.
Merlin is best known as the mighty wizard featured in Arthurian legend. The standard depiction of the character first appears in Geoffrey of Monmouth's Historia Regum Britanniae, and is based on an amalgamation of previous historical and legendary figures. Geoffrey combined existing stories of Myrddin Wyllt (Merlinus Caledonensis), a northern madman with no connection to King Arthur, with tales of Aurelius Ambrosius to form the figure he called Merlin Ambrosius.
Merlin is a 3 hour made-for-television movie released in 1998 that retells the famous legend of King Arthur from the perspective of the wizard Merlin. Sam Neill stars in the title role in a story that covers not only the rise and fall of Camelot but also the phase, supposedly in the history of the British Isles, that had preceded it. According to this version of the famous Arthurian tale, the power of the pagan goddess Mab, played by Miranda Richardson, is waning due to the coming of Christianity to Great Britain, and she creates Merlin in hope of keeping the "Old Ways" alive.
Merlin (sometimes known as Merlin, the Electronic Wizard) was a handheld electronic game first made by Parker Brothers in 1978. Merlin is notable as one of the earliest and most popular handheld games, selling over 5 million units during its initial run, as well as one of the most long-lived, remaining popular throughout the 1980s. A version of the game has been recently re-released by the Milton Bradley Company.
Merlin is the narrator and main character in the second half of the Chronicles of Amber by American science fiction author Roger Zelazny. He is an incidental character in the first half of the series, eventually being revealed to be the listener to whom Corwin relates the tale of his attempts to take the throne of Amber, and dealing with the subsequent invasion from Chaos.
Merlin was a Broadway musical which ran for approximately six months in 1983. It was based on a concept by popular illusionist Doug Henning and Barbara De Angelis. It purported to tell the story of the legendary magician/wizard Merlin ... not as an elderly man (as Merlin is usually depicted) but as a young man (played by Henning), still an apprentice wizard learning the rules of magic.