# correlation

Pronunciation: say "kor-uh-LAY-shuhn" US /ˌkɔɹ.əˈleɪ.ʃən/, UK /ˌkɒɹ.əˈleɪ.ʃən/

## Noun

1. A reciprocal, parallel, or complementary relationship between two or more comparable things, where changes in one correspond to changes in another.
   - Simple: A link between two or more things, where they change together in a connected way.
   - _Researchers noted a striking correlation between rising temperatures and crop failure._
   - _The correlation between the two datasets surprised the analysts._
2. In statistics, any of several measures of how strongly, and in which direction, two random variables are linearly related.
   - Simple: A number that shows how strongly two things are linked and whether they rise or fall together.
   - _Analysts reported a correlation of 0.85 between the two stock indices._
   - _A weak correlation between the variables suggested little predictive value._
3. In projective geometry, an isomorphism between a projective space and the dual of a projective space, often its own dual.
   - Simple: A special matching in geometry that links the points of one space to the lines or planes of a related space.
   - _A correlation maps each point of the projective plane to a line in the dual plane._
   - _Composing a correlation with itself yields a projective collineation._

## Origin

Borrowed from Middle French corrélation, and analyzable as 'correlate' plus the suffix '-ion'.

Source: DictionaryAI, https://dictionaryai.com/define/correlation (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).