Neverland (also spelled Never Land and also known as Never Never Land) is a fictional world featured in the works of J. M. Barrie and those based on them.
People in Neverland may cease to age if they so choose and it's best known resident famously refused to grow up, so it is often used as a metaphor for eternal childhood (and childishness), immortality, and escapism. Neverland has been featured prominently in subsequent works, either adapting Barrie's work or expanding upon them. These Neverlands sometimes vary in nature from the original, which seems fitting as Barrie originally described them as doing that.
According to the original work, it is a physical manifestation of children's dreams, and is able to be reached through a child dreaming, but only for a short time using this method. However, it is possible to physically go there, and even to become a permanent resident.