officially = 'conclusively; definitively'

[Jonathan Lighter]

Not in OED.  Common in the media for (maybe) thirty or forty years.  I used
to think it was intentionally humorous, but now I doubt it

1998 Lloyd L. Lee, ed. _World War 2 in Asia and the Pacific_ [Greenwood
Press] 294: The Battle of Britain, which began in July, 1940, officially
brought the devastation of war home to Britain.

JL

--
"If the truth is half as bad as I think it is, you can't handle the truth."

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