Definitions for "day lily"
any plant of a genus of plants (Hemerocallis) closely resembling true lilies, but having tuberous rootstocks instead of bulbs. The common species have long narrow leaves and either yellow or tawny-orange flowers, which often bloom for only one day.
A genus of plants (Funkia) differing from the last in having ovate veiny leaves, and large white or blue flowers.
any of numerous perennials having mounds of sumptuous broad ribbed leaves and clusters of white, blue, or lilac flowers; used as ground cover