The flat bar which carries the nonius scale and index-glass of a quadrant, octant, quintant, or sextant.
Excluded, of course, are those instruments normally made of wood, such as the octant and the mariners quadrant.
It is the sextant or some member of the sextant family - such as the quadrant, octant, etc.
octant made of dark wood and with lignum vitae; brass fittings.
It was in its octant, and showed a crescent finely traced on the dark background of the sky.
Thus fig. 59 conveniently represents an octant of the wave surface, which cuts each coordinate plane in a circle and an ellipse.
A third staff (or an octant) was fixed at the end of the horizon-staff, and upon it the angle observed could be read off.