The two creations,—the extinct and the extant,—or rather the prochronic and the diachronic—here unite.
Now, again I repeat, there is no imaginable difference to sense between the prochronic and the diachronic development.
1857, from Greek dia "throughout" (see dia-) + khronos "time" (see chrono-). Use in linguistics dates from 1927.
diachronic di·a·chron·ic (dī'ə-krŏn'ĭk)adj. Of or concerned with phenomena as they change through time.