locus

noun (plural loci /-sʌɪ, -kʌɪ, -kiː/)

• 1 technical a particular position or place where something occurs or is situated:it is impossible to specify the exact locus in the brain of these neural events
• the effective or perceived location of something abstract:the real locus of power is the informal council
• Genetics the position of a gene or mutation on a chromosome.

• 2 Mathematics a curve or other figure 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: a parabola is the locus of a point that moves so as to be equidistant from a fixed point and a straight line

• 3 Lawshort for locus standi.