- In genetics, the locus is the position on a chromosome where a specific gene is located.
- In mathematics, a locus is the set of all points (usually forming a curve or surface)
that satisfy some condition. For example, the locus of points in the
plane equidistant from a given point is a circle. Plural is "loci".
The Latin word locus simply means "place." (The Greek equivalent
is topos, which crops up in "topology".)