0 Old HSK word(s):
中流砥柱* *

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

中 central / center, middle / in the midst of / hit (target) / attain
流 flow, circulate, drift / class
砥 a whetstone / to polish
柱 pillar, post / support / lean on
Hsk Characters:
HSK -Characters and beyond:
GbBig5EngRadMegaTripleMultilingual