quadrant

A circular arc of 90°; one fourth of the circumference of a circle.

The plane area bounded by such an arc and two perpendicular radii.

Any of the four areas into which a plane is divided by the reference axes in a Cartesian coordinate system, designated first, second, third, and fourth, counting counterclockwise from the area in which both coordinates are positive.

A machine part or other mechanical device that is shaped like a quarter circle.

An early instrument for measuring altitude of celestial bodies, consisting of a 90° graduated arc with a movable radius for measuring angles.

Square.

In embryology, one of the four blastomeres or cleavage-cells in the four-cell stage of the ovum.

A square or one of its sides.

An oscillating arm attached to a spinning-mule to give a proper rotation to the spindles during the winding of the yarn on the cop.