Definify.com
Webster 1913 Edition
Locus
1.
A place; a locality.
2.
(Math.)
The line traced by a point which varies its position according to some determinate law; the surface described by a point or line that moves according to a given law.
Plane locus
, a locus that is a straight line, or a circle.
– Solid locus
, a locus that is one of the conic sections.