What are coral reefs also called?

"Polyps are colonial corals" Seems that people like me would call reefs something other than rainforests

Kiwozzie, I hope they are successful in preserving the Great Barrier Reef. I'm in the US, but I have a friend who teaches scuba diving in that reef. He's very concerned with it's condition.

Unfortunately the Great Barrier Reef is declining steadily with coral bleaching and chemical run offs, rising temperatures, they are taking samples of what is left & putting them in like a seed bank, but for coral.