Class: directrix
http://www.astro.umd.edu/~eshaya/astro-ont/owl/geometry.owl#directrix
-
shape
-
one-D_Shape
-
line
- directrix
-
line
-
one-D_Shape
Annotations
- definition: "A parabola is the set of points equidistant from the focus and the directrix line." (string)