Definition.
Coined by scholar Henri Corbin to distinguish it from the oft-dismissed domain of the imaginary, the imaginal pertains to the subtle experiences of the inner world. Similar to the Greek onar (the world of dream, as opposed to the hypar, the material world), we engage the imaginal by way of the faculty of imagination.
An expanded reading about the concept of the imaginal can be found in the article, Imaginal research: Exploring the unconscious psyche.