Definition of sodium metaphosphate
1
: any of several crystalline sodium salts NaPO3 or (NaPO3)n of a metaphosphoric acid: such as
a
: the water-soluble cyclic trimetaphosphate (NaPO3)3 or NaPO3 I
b
: sodium Kurrol's salt NaPO3 IV
2 a
: a water-soluble sodium phosphate glass having the composition of a sodium metaphosphate — called also
sodium (1:1) phosphate; compare sodium hexametaphosphate
