Basically, gravity is the force which forms an attraction between two objects with mass.
So, was the apple really the core of Newton's revolutionary findings? Or was it but a seed from which his knowledge and insights grew?
The apple analogy is indeed a precious anecdote in physical science, perhaps bringing a hint of poetic licence to the otherwise highly rational discipline. However, the apple story has been tweaked. There is no written account by Newton himself crediting his findings to a bump on the head by a falling fruit.
Contrary to what popular myth suggests, Newton didn't have an epiphany the instant the apple supposedly struck him on the cranium. His work was the product of many years' scholarly correspondance and painstaking research.
Of course, generations of shining, polishing and sensationalism have cleaned up the story of Newton's apple, which has been described by Stephen Hawking in his record-breaking bestseller, A Brief History of Time as 'almost certainly apocryphal.'
The memoirs of William Stukely, a younger contemporary of Newton, quoted the illustrious Cambridge University representative with the following:
Why sh[oul]d that apple always descend perpendicularly to the ground, thought he to himself; occasion'd by the fall of an apple, as he sat in contemplative mood.
But was it really a rogue apple accelerating to the ground that inspired Newton's ground-breaking research on gravity?
If so, I'll bet that apple would be worth almost as much as the one Satan used to tempt Adam and Eve in the Garden of Eden. But I guess that was a couple of generations back. Perhaps gravity was yet to be created.