Entry 2 senses · 2 variants Webster, 1913 Polystome · Pol·y·stome · IPA a. n. 01 a. Having many mouths. 1. Having many mouths.(Zool.) 02 n. An animal having many mouths; -- applied to Protozoa. 1. An animal having many mouths; -- applied to Protozoa.(Zool.)