Reformation - Vine's Expository Dictionary of New Testament Words
Reformation[ 1,,G1357, diorthosis ]
properly, a making straight" (dia, "through," orthos, "straight;" cp. diorthoma in Acts 24:2; See CORRECTION, No. 1), denotes a "reformation" or reforming, Hebrews 9:10; the word has the meaning either
(a) of a right arrangement, right ordering, or, more usually,
(b) of restoration, amendment, bringing right again; what is here indicated is a time when the imperfect, the inadequate, would be superseded by a better order of things, and hence the meaning
(a) seems to be the right one; it is thus to be distinguished from that of Acts 24:2, mentioned above. The word is used in the papyri in the other sense of the rectification of things, whether by payments or manner of life.