0 Old HSK word(s):
暗礁* * 触礁* * 礁* * 珊瑚礁* *

Definitions from Unihan Copyright © 1991-2015 Unicode® Inc. All rights reserved.

珊 coral
瑚 coral / person of virtue
礁 reef / jetty / submerged rocks

Hsk Characters:
HSK -Characters and beyond:
GbBig5EngRadMegaTripleMultilingual
礁 7901 + 礁 + + reef / jetty / submerged rocks 石 焦 Stone 焦 (VERBRANNT) jiao1 +

Korean:

礁 + 礁 물에잠긴바위초
嶕 + 礁 높을 초
0 NHSK word(s):
KOREAN6000 word(s):
0 KOREAN 2500 New HSK words):
0 KOREAN Sentence(s):