Ir`re*solv"a*ble (?), a. [Pref. ir- not + resolvable. Cf. Irresoluble.]
Incapable of being resolved; not separable into component parts.
Irresolvable nebulae Astron., nebulae of a cloudlike appearance, which have not yet been resolved by the telescope into stars.<-- Which are often galaxies: see under Galaxy "the term has recently  been used for remote clusters of stars" -->
Sir W. Herschel.
© Webster 1913.