I. ˈpäd.ˌash, -äˌta-, -aash, -aish noun
Etymology: singular of pot ashes (from pot (I) + ashes, plural of ash ), translation of obsolete Dutch potaschen, plural (whence obsolete Dutch potasch, singular, now Dutch potas )
1.
a. : potassium carbonate ; especially : that obtained in colored impure form by leaching wood ashes, evaporating the lye usually in an iron pot, and calcining the residue — compare pearl ash
b. : potassium hydroxide
2.
a. : potassium oxide K 2 O in combined form as determined by analysis (as of fertilizers)
soluble potash
b. : potassium — not used systematically
potash salts
sulfate of potash
3. : any of several potassium salts (as potassium chloride or potassium sulfate) often occurring naturally and used especially in agriculture and industry
potash deposits
potash fertilizers
II. transitive verb
: to treat with potash ; specifically : to case harden with potassium ferrocyanide