Bissextile :: Bissextile (n.) Leap year; every fourth year, in which a day is added to the month of February on account of the excess of the tropical year (365 d. 5 h. 48 m. 46 s.) above 365 days. But one day added every four years is equivalent to six hours each year, which is 11 m. 14 s. more than the excess of the real year. Hence, it is necessary to suppress the bissextile day at the end of every century which is not divisible by 400, while it is retained at the end of those which are divisible by 400..
Semisextile :: Semisextile (n.) An aspect of the planets when they are distant from each other the twelfth part of a circle, or thirty degrees..
Sextic :: Sextic (a.) Of the sixth degree or order.
Sextic :: Sextic (n.) A quantic of the sixth degree.
Sextile :: Sextile (a.) Measured by sixty degrees; fixed or indicated by a distance of sixty degrees.
Sextile :: Sextile (n.) The aspect or position of two planets when distant from each other sixty degrees, or two signs. This position is marked thus: /..
Sextillion :: Sextillion (n.) According to the method of numeration (which is followed also in the United States), the number expressed by a unit with twenty-one ciphers annexed. According to the English method, a million raised to the sixth power, or the number expressed by a unit with thirty-six ciphers annexed. See Numeration..