Wiktionary
n. A short integrating a song and imagery, produced for promotional or artistic purposes.Dan Moller, 'Redefining Music Video' 2011, http://danmoller.com.au/?p=87
Wikipedia
A music video is a short film integrating a song and imagery, produced for promotional or artistic purposes. Modern music videos are primarily made and used as a marketing device intended to promote the sale of music recordings. There are also cases where songs are used in tie in marketing campaigns that allow them to become more than just a song. Tie ins and merchandising could be used in toys or marketing campaigns for food and other products. Although the origins of music videos date back to musical short films that first appeared in the 1920s, they came into prominence in the 1980s when MTV based their format around the medium. Prior to the 1980s, these works were described by various terms including " illustrated song", "filmed insert", "promotional (promo) film", "promotional clip", "promotional video", "song video", "song clip" or "film clip". Since the creation and increased popularity of YouTube, mainstream artists now promote new music videos by releasing trailers of short promos on the site for their upcoming song and music video. Consequentially, YouTube has been converted into a social media platform for celebrities and artists to market themselves to their fans and audiences.
Music videos use a wide range of styles of contemporary video making techniques, including animation, live action filming, documentaries, and non-narrative approaches such as abstract film. Some music videos blend different styles, such as animation, music, and live action. Combining these styles and techniques has become more popular because of the variation it resent to the audience. Many music videos interpret images and scenes from the song's lyrics, while others take a more thematic approach. Other music videos may be without a set concept, being merely a filmed version of the song's live performance. Music videos have also become a place where product placement is evident in almost every mainstream video. They are always parent and it usually takes place because the artist is sponsoring a product or brand. An example of product placement is the Beats Pill being featured in numerous hip hop videos. The strong emphasis on product placement is something that has evolved because of the global scale music videos can reach because of websites such as YouTube.