Taken from this blog, the Flipped Classroom as described by Jonathan Martin is:
Flip your instruction so that students watch and listen to your lectures for homework, and then use your precious class-time for what previously, often, was done in homework: tackling difficult problems, working in groups, researching, collaborating, crafting and creating. Classrooms become laboratories or studios, and yet content delivery is preserved.
Jardine, D. (2006). "Youth need images for their imaginations and for the formation of their memories." Journal of Curriculum Theorizing. 22(4), 3-12.