I am researching Julia sets and Mandelbrot sets and am having some difficulty understanding what the term "seed" means in this case:

"The filled Julia set for x2 + c is the collection of all seeds whose orbit does not escape to infinity under iteration of x2 + c. Thus there is a different filled Julia set for each c-value. "

Thanks for your help, i just need some1 to explain what it means. I've had a thorough search on Google and it doesn't explain it anywhere!

Also, if you have a little time could u explain what the similarities between Mandelbrot set and Julia set is but the meaning is my first priority. Thankyou