Potass and Potassium

Potassium and potass are semantically related. In some cases you can use "Potassium" instead the word "Potass" as a noun or an adjective.

Potassium noun - A light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite.

Potass and potassium are semantically related. Sometimes you can replace term "Potass" with "Potassium", this nouns are similar.