Octahedron
in geometry, a solid contained by eight equal and equilateral angles. It is one of the five regular bodies.
OCTANS ("the Octant"), the constel lation surrounding and including the South Pole of the heavens, and one of the 14 added to the heavens by Lacaille in connection with his work at the Cape of Good Hope. Its brightest star is of the 3.8 magnitude. The star Sigma Octantis, of the 5.8 magnitude, lies at present within about 3/4° of the South Pole, nearer than any equally bright star to the North Pole, and it is much used in the Southern Hemisphere for the determination of the azimuth of transit instruments. The constellation is sur- ODD FELLOW