the world > relative properties > order > agreement, harmony, or congruity > suitability or appropriateness > [noun] > that which is suitable or appropriate
1768 L. Sterne I. 90 It occurred to me, that that was the very thing.
1802 J. West II. 123 This behaviour was certainly the very thing.
1868 Newman Let. in July (1909) 66 I am both surprised and glad at your news... I think it is the very thing for you.