1. United or inseparable in essence or being.
1471. Ripley, Comp. Alch., in Ashm. (1652), 112. All the parts … be Coessentiall and concrete.
1618–29. in Rushw., Hist. Coll. (1659), I. 335. There are other Laws that be coessential and collateral with Government.
1675. Art Contentm., Pref. 175. The desire of happiness is so coessential with our nature.
2. One in essence, having the same essence; esp. in Theol. of the Persons of the Trinity.
1587. Golding, De Mornay, v. 51. Coeternall, Coequall, and Coessentiall, that is to say … of one selfesame substance or beeng.
1597. Hooker, Eccl. Pol., V. (1617), 290. Wee blesse and magnifie that Coessentiall Spirit eternally proceeding from both.
1713. Beveridge, Priv. Th., I. (1730), 30. As they are from Eternity Three perfectly distinct Persons, so they are but one Co-essential GOD.
1862. F. Hall, Hindu Philos. Syst., 233, note. The latter hold them [substance and quality] to differ in their very essence; while the former consider them to be coessential.
3. Jointly essential or necessary. nonce-use.
1876. E. Mellor, Priesth., iv. 158. Both were coessential factors in the last supper, the latter completing the former.
