cossistEtymologyFrom Italian cossista, from the word cosa (“thing”), in reference to an unknown quantity to be determined + -ista. See rule of coss.cossist means pertaining to the cossists and their methods; cossic. Lexicurio rates it Rare gem — a strength score of 74 out of 100.adjPertaining to the cossists and their methods; cossic.“Clavius's treatise is, first of all, reckoned as one of the textbooks of cossist algebra.”nounA practitioner of proto-algebra in Renaissance and Early Modern Europe.“The word "cossist" comes from the Italian cosa, meaning "thing." The cosa was the mystery that algebra was designed to solve -- it was the name given to the unknown quantity in an equation (our modern x).”