Definition of: locus

(lō′kəs) noun plural ·ci (-sī)
1. A place; locality; area.
2. Math. A surface or curve regarded as traced by a line or point moving under specified conditions; any figure made up wholly of points or lines that satisfy given conditions.
3. A figure formed by the foci of a series of pencils of light.
4. A passage in a writing.
5. plural A series of passages, as from the Scriptures, classified for reading or study; any book containing such passages.
6. Genetics The linear position of a gene on a chromosome. [<L. Doublet of LIEU.]