Gorgonian and Red coral

Gorgonian noun - Corals having a horny or calcareous branching skeleton.

Red coral and gorgonian are semantically related. In some cases you can replace phrase "Red coral" with "Gorgonian", this terms are similar.

Red coral noun - Corals of especially the Mediterranean having pink or red color used for ornaments and jewelry.

Gorgonian and red coral are semantically related. You can use "Gorgonian" instead a noun phrase "Red coral".