“+...- noun
Etymology: phosph- + tungstic
: any of several heteropoly acids obtainable from solutions of phosphoric acid and tungstic acid and used chiefly as precipitants (as for alkaloids and for basic dyes for pigments) and in analytical reagents ; especially : the greenish yellow crystalline acid H 3 PW 12 O 40 . x H 2 O containing twelve atoms of tungsten in the molecule — called also tungstophosphoric acid