lily of the valley noun2 •A flowering plant, Convallaria majalis, with richly fragrant pendant bells.Oh, what a perfect thought. Lilies-of-the-valley, and white pansies, double white violets and white velvet ribbon… From an unknown friend. … From one who understands. … For a Little Girl. — 1920 •A flower of this plant. formsLilies of the Valley · lilies of the valley · lilies-of-the-valley