[f. COR- + RELATION: cf. F. corrélation, and see CORRELATIVE.]
1. The condition of being correlated; mutual relation of two or more things (implying intimate or necessary connection).
1561. T. Norton, Calvin’s Inst., IV. xvii. § 14. If he did set before vs only an empty imaginatiue forme of bred … where were ye correlation or similitude [analogia aut similitudo] which should leade vs from the visible thing to the inuisible.
1658. Sir T. Browne, Gard. Cyrus, iii. How in animall natures, even colours hold correspondencies, and mutuall correlations.
1849. Murchison, Siluria, viii. 148. The rocks of Cumberland will be placed in precise correlation with the types of Shropshire and Wales.
1864. Bowen, Logic, iii. 51. The mutual dependence and correlation of these three Axioms.
† b. Relationship (of persons). Obs.
1649. Jer. Taylor, Gt. Exemp., Ad sect. 10 ¶ 9. Christian charity is a higher thing than to be confined within the terms of dependence and correlation.
1652. Sparke, Prim. Devot. (1663), 89. Christ … made choise of brethren, as … Simon … and Andrew … hereby … providing against schisme … both by corporall and spirituall correlation.
2. Correlation of forces (in Physics): a phrase introduced by Grove to express the mutual relation that exists between the various forms of force or energy, by virtue of which any one form is convertible into an equivalent amount of any other. (Cf. conservation of energy, s.v. CONSERVATION 4.)
1843. Grove, Correlation of Physical Forces, 95. The sense I have attached to the word correlation … [is] a reciprocal production; in other words, that any force capable of producing another, may in its turn be produced by it.
1869. Mrs. Somerville, Molec. Sc., I. ii. 33. Another proof of the correlation of heat and electricity.
3. Biol. Mutual relation of association between different structures, characteristics, etc., in an animal or plant; ‘the normal coincidence of one phenomenon, character, etc., with another’ (Darwin, Orig. Species, Gloss.).
1859. Darwin, Orig. Spec., Introd. i. 9. The complex … laws of variation and of correlation of growth…. Some instances of correlation are quite whimsical: thus cats which are entirely white and have blue eyes are invariably [ed. 1878 generally] deaf.
1870. Rolleston, Anim. Life, 105. The correlation of large size of ova with the completion of development before hatching.
1883. E. Kay Robinson, in 19th Cent., May, 763. There is … a mysterious law of correlation of growth between the hair and the teeth.
4. Geom. The reciprocal relation between propositions, figures, etc., derivable from each other by interchanging the words point and plane, or point and line: cf. CORRELATIVE a. 6.
5. The action of correlating or bringing into mutual relation.
1879. Geo. Eliot, Theo. Such, xi. It is on such false correlations that men found half their inferences about each other.
