What does locus mean?
A locus is a defined place, position, or point, especially within a larger spatial, biological, or abstract system. In general use, the word may identify the centre or site of an activity, influence, or dispute. Its most important technical use is in genetics, where a locus is the precise position of a gene or genetic marker on a chromosome; a locus can contain one gene or multiple genes. The word is also used in formal writing for a focus or centre of power, activity, or attention. Unlike location, which can be broad or indefinite, a locus usually suggests a more precisely identified position within a defined system. Locus is therefore valuable in academic, scientific, and analytical contexts, where specificity matters, although it is less common in ordinary conversation.
nounA particular position, place, or point in space or in an abstract system. In genetics, a locus is the fixed position of a gene or genetic marker on a chromosome.
- A particular place, position, or point in space or within a larger structure.
- The position of a gene or genetic marker on a chromosome.
- A position or area associated with a particular function, activity, or phenomenon.
"The locus of the dispute was the proposed change to the town's planning rules."
"The painting's locus was the northern wall of the chapel."
"Researchers identified a genetic locus associated with increased risk of the disease."
The standard plural is loci, pronounced “LOH-kee” or “LOH-keye” in scientific usage.
"Several genetic loci were associated with the trait in the study population."
In genetics, a locus is a precise address: it tells you where a gene or genetic marker sits on a chromosome.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does locus come from?
Locus comes from Latin, where it means “place” or “position.” Latin locus also contributed to English words such as local, locate, and location. The English scientific use for a fixed position on a chromosome developed from this general sense of an assigned place, with loci serving as the plural.
Related word forms
How locus is actually used
The word is formal and relatively uncommon in everyday speech, though it is standard in academic and scientific writing. In genetics, it refers specifically to a fixed chromosomal position rather than to the gene's function.
Easily confused with locus
Loci is the plural form of locus, especially when referring to fixed positions of genes on chromosomes.