Correlation (-l?sh?n), n. [LL. correlatio; L. cor- + relatio: cf. F. corrélation. Cf. Correlation.] Reciprocal relation; corresponding similarity or parallelism of relation or law; capacity of being converted into, or of giving place to, one another, under certain conditions; as, the correlation of forces, or of zymotic diseases.
[1913 Webster]

Correlation of energy, the relation to one another of different forms of energy; -- usually having some reference to the principle of conservation of energy. See Conservation of energy, under Conservation. -- Correlation of forces, the relation between the forces which matter, endowed with various forms of energy, may exert.
[1913 Webster]