| Cissoid | n. [ Gr. &unr_; like ivy; &unr_; ivy + e'i^dos form. ] (Geom.) A curve invented by Diocles, for the purpose of solving two celebrated problems of the higher geometry; viz., to trisect a plane angle, and to construct two geometrical means between two given straight lines. [ 1913 Webster ] |
| Discoid | a. [ Gr. &unr_; quoit-shaped, &unr_; a round plate, quoit + e'i^dos 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. [ 1913 Webster ]
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. [ 1913 Webster ]
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