locus

(lōˈkəs)

1. A locality; a place.
2. A center or focus of great activity or intense concentration: “the cunning exploitation of loci of power; the insulation from normal American society” (Clifton Fadiman).
3. Mathematics The set or configuration of all points whose coordinates satisfy a single equation or one or more algebraic conditions.
4. The position that a given gene occupies on a chromosome.