Locus

How to spell locus

5 letters · 2 syllables

How to pronounce locus

Say the part in capitals loudest.

What does locus mean?

1. nounThe particular place or point where something is concentrated or where it happens.
2. nounThe set of all points that satisfy a given condition, often forming a line or curve.
3. nounThe fixed position of a gene or marker on a chromosome.

Locus in a sentence

• The trading floor was the locus of all the day's activity.

• The teacher showed that the locus of points equidistant from a centre is a circle.

• Researchers mapped the disease to a single locus on chromosome seven.

• Investigators identified the warehouse as the locus of the fraud.

• Each curve on the diagram represents a locus defined by a single equation.

• Each locus can carry different versions of the same gene.

Where does locus come from?

Language of origin: Latin

Locus is the Latin word for 'place' or 'position', taken straight into English without alteration in the early seventeenth century. In Latin it could mean a literal spot of ground, a passage in a text, or a topic of discussion, and that flexibility carried over into its scholarly English uses. Mathematicians adopted it to name the set of points that satisfy a given condition, treating a curve or line as the 'place' where such points live. Geneticists later borrowed the same idea for the fixed 'place' a gene occupies on a chromosome. The word keeps its Latin plural, loci, and shares its root with everyday relatives such as 'location', 'local', and 'allocate', which is a useful reminder that the spelling ends in a plain -cus rather than the more familiar -cous or -kus.

How the word is built

• locus (Latin: place, position), borrowed whole with no English affixes