| Noun | 1. | greater water parsnip - large stout white-flowered perennial found wild in shallow fresh water; Europegenus Sium, Sium - perennial of wet and marshy places in the northern hemisphere: water parsnips bog plant, marsh plant, swamp plant - a semi-aquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath | |