sodium tripolyphosphate

[ trahy-pol-ee-fos-feyt ]
/ ˌtraɪ pɒl iˈfɒs feɪt /

noun Chemistry.

a white powder, Na5P3O10, used as a water softener, sequestering agent, and food additive.
Also called sodium triphosphate.

Origin of sodium tripolyphosphate

First recorded in 1940–45; tri- + poly- + phosphate