Various Artists often abbreviated as VA or V/A is a term used by the music industry for releases (singles or albums) that contain collaborations. Rather than listing the many individual singers or artists being credited individually, the name Various Artists is used instead.
Aggregated compilation albums containing tracks from a number of artists can also be credited to Various artists. Various Artists compilation albums are often compiled from a particular musical style or period to another.
There are also charity records released that may use the term rather than mentioning specific artists, e.g. USA for Africa or Band Aid.
Another use for Various Artists is a specific artist "and Various Artists" or "featuring Various Artists". This is most common in remixes where there are many releases using the formula, like Rihanna ft. Various Artists for remixes of "What's My Name?".
This practice is in line with the term "and Friends" like in the song "That's What Friends Are For" credited to "Dionne Warwick & Friends" (rather than various artists).