Definition of "diachronic"

[…] one salient value of archival magazine preservation is that individual issues register, however unintentionally, the small, incremental, diachronic movements within a culture.

2005 April 24, Los Angeles Times

It is plain that natural science has developed more diachronic concern, more of the longer historical approach in its interests and repertory, in the last two centuries than in the two millennia before.

1963, Alfred Louis Kroeber, An Anthropologist Looks at History‎, page 169

I also take a more diachronic perspective and relate the growth of empire to changes in the regional market system as they occurred in the transition from the Early Aztec to the Late Aztec periods.

1996, Richard E. Blanton, “3: The Basin of Mexico Market System and the Growth of Empire”, in Frances Berdan, editor, Aztec Imperial Strategies, page 52

In short, it's usual for the syuzhet to appear more diachronic at the beginning and more synchronic at the end.

2011, Herman Rapaport, The Literary Theory Toolkit: A Compendium of Concepts and Methods‎, page 82

Rethinking the revolution issue is therefore the key to any novel interpretation, but it needs to be addressed in a more diachronic and synchronic fashion, comparing the Wende to earlier German upheavals and to the concurrent transformation of East Central Europe.

2011, Konrad H. Jarausch, “Chapter One: Germany 1989: A New Type of Revolution?”, in Marc Silberman, editor, The German Wall, page 11

Consequently, the perspective will be more diachronic than synchronic.

2012, Paolo Ramat, Sturtevant's paradox revisited, Thomas Stolz, Hitomi Otsuka, Aina Urdze, Johan van der Auwera (editors), Irregularity in Morphology (and Beyond), [page 61]

However, his interpretation and conclusion receive their rationale almost as often from the subjective horizon as the more diachronic oriented commentaries do.

2012, Oliver Glanz, Understanding Participant-Reference Shifts in the Book of Jeremiah‎, page 172