Also 7–8 cohæsion. [a. F. cohésion, ad. L. *cohæsiōn-em, n. of action f. cohæs- ppl. stem of cohærēre to COHERE.]
1. The action or condition of cohering; cleaving or sticking together; spec. the force with which the molecules of a body or substance cleave together: cf. ATTRACTION of Cohesion.
1678. Hobbes, Nat. Philos., viii. Wks. 1845, VII. 139. The parts thereof may be contiguous, without any other cohesion but towch.
1690. Locke, Hum. Und., II. v. (1695), 54. The Extension of Body, being nothing but the Cohesion or continuity of solid separable, moveable Parts.
1765. A. Dickson, Treat. Agric., IV. iv. (ed. 2), 468. Where the cohesion is weakest, it opens in rents.
1865. Geikie, Scen. & Geol. Scot., ii. 35. Water … loosens the cohesion of a steep bank.
1870. Tyndall, Heat, i. 9–10. He wishes to tear the wood asunder, to overcome its mechanical cohesion by the teeth of his saw.
2. Bot. The superficial union of like organs. (Distinguished from ADHESION.)
1835. Henslow, Bot. (Lardner’s Cabinet Cycl.), 93. In proportion as this cohesion extends from the base towards the apices of the sepals.
1848. Lindley, Introd. Bot., II. 62. A cohesion of the cotyledons takes place.
1882. Vines, Sachs’ Bot., 546, note. It has come to be the usage in English works on descriptive botany to apply the term ‘cohesion’ to the apparent union of organs of the same kind, ‘adhesion’ to the apparent union of organs of a different kind.
3. transf. and fig. Of non-material union.
c. 1698. Locke, Cond. Underst. § 39 (1741), 99 (J.). In their tender Years Ideas, that have no natural Co-hesion come not to be united in their Heads.
1796. Burke, Regic. Peace, i. Wks. 1808, VIII. 161. It long held together with a degree of cohesion, firmness, and fidelity not known before or since in any political combination of that extent.
1855. H. Spencer, Princ. Psychol. (1872), I. II. ii. 180. There is considerable cohesion between the visual sensations produced by an orange and the taste or smell of the orange.
1875. Stubbs, Const. Hist., I. ii. 28. The tie of nationality [was] a sufficient bond of cohesion.
4. attrib., as in Cohesion figures: the forms assumed by a drop of any liquid when placed on a solid or another liquid.
