Locus \Lo"cus\, n.; pl. {Loci}, & {Loca}. [L., place. Cf. {Allow}, {Couch}, {Lieu}, {Local}.] 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.
Oliver LaFarge is a genius loci of this landscape.