Dis″coid (?), a. [Gr. � quoit-shaped, � a round plate, quoit + � form, shape: cf. F. discoïde. See Disk.] Having the form of a disk, as those univalve shells which have the whorls in one plane, so as to form a disk, as the pearly nautilus.
Discoid flower(Bot.), a compound flower, consisting of tubular florets only, as a tansy, lacking the rays which are seen in the daisy and sunflower.