DIONYSIAN
Di`o*ny"sian, a.
Defn: Relating to Dionysius, a monk of the 6th century; as, the Dionysian, or Christian, era. Dionysian period, a period of 532 years, depending on the cycle of the sun, or 28 years, and the cycle of the moon, or 19 years; — sometimes called the Greek paschal cycle, or Victorian period.
DIOPHANTINE
Di`o*phan"tine, a.
Defn: Originated or taught by Diophantus, the Greek writer on algebra. Diophantine analysis (Alg.), that branch of indeterminate analysis which has for its object the discovery of rational values that satisfy given equations containing squares or cubes; as, for example, to find values of x and y which make x2 + y2 an exact square.
DIOPSIDE
Di*op"side, n. Etym: [Gr. diopside.] (Min.)
Defn: A crystallized variety of pyroxene, of a clear, grayish green color; mussite.
DIOPTASE
Di*op"tase, n. Etym: [Gr. dioptase.] (Min.)
Defn: A hydrous silicate of copper, occurring in emerald-green crystals.
DIOPTER; DIOPTRA
Di*op"ter, Di*op"tra, n. Etym: [L. dioptra, fr. Gr. Dioptric.]
Defn: An optical instrument, invented by Hipparchus, for taking altitudes, leveling, etc.