What is a "parachute effect" when talking about scuba/snorkel/freediving fins?

I have just started scuba diving in the past few weeks and I am slowly starting to buy my own basic gear (mask, snorkel, fins, rash guard, etc.) I have enjoyed it a lot, so I feel that I will continue diving and I will be putting the gear to good use. When i look around online for fins, a lot of them declare that they have eliminated "parachute effect" in their new designs. Is this something important that I should be concerned about? I tried researching online but all that comes up is products that eliminate the effect- however, nothing describes what it is. Can a more scuba savvy person help me out? Im sure its just something simple, but nevertheless it has made me very curious.