Entry 1 sense Webster, 1913 Water star grass /wôt'-ẽr stär grăs/ · Wa·ter star· grass · IPA 01 An aquatic plant (Schollera graminea) with grassy leaves, and yellow star-shaped blossoms. 1. An aquatic plant (Schollera graminea) with grassy leaves, and yellow star-shaped blossoms.(Bot.)