Definitions for "Quadrants"
Keywords:  dentists, axes, ease, cusp, chart
there are 4 "quadrants" in a chart, and each starts at the cusp of the first, fourth, seventh, and tenth houses. (read about hemisphere emphasis).
The four regions of a coordinate plane that are separated by the axes.
For ease of reference, dentists talk of quadrants in the mouth. There are four of these; two upper and two lower; each with right and left.