0 Old HSK word(s):
套公式* *

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

套 case, cover, wrapper, envelope
公 fair, equitable / public / duke
式 style, system, formula, rule

Hsk Characters:
HSK -Characters and beyond:
GbBig5EngRadMegaTripleMultilingual