define: locus
Medical Definition of locus. plural. loci. \ËlÅ-ËsÄ«, -ËkÄ« also -ËkÄ\play play play. 1: a place or site of an event, activity, or thing the integrity of the tissues determines the extent and locus of the damageâSylvia E. Hines. 2: the position in a chromosome of a particular gene or allele.