Английский разговорный словарь (основной) - locus

ˈləukəs n. (pl. loci) 1 a position or point, esp. in a text, treatise, etc. 2 Math. a curve etc. formed by all the points satisfying a particular equation of the relation between coordinates, or by a point, line, or surface moving according to mathematically defined conditions. 3 Biol. the position of a gene, mutation, etc. on a chromosome. [L, = place]