[tz] Definition of "timezone"

[Steve Allen]

On Thu 2023-12-21T18:12:27-0500 Dale Ghent via tz hath writ:
> We all know UTC is not a time zone, but rather a time coordinate.
> It just happens to coincide with GMT, so why not?

Even here there are problems with historical usage where the
terminology does not mean what almost everyone thinks it seems.
The value that has been provided using the name GMT started deviating
systematically from the mean solar time of the Greenwich meridian
in 1901.  The convention that drives the deviation is unavoidable
because the true goal of the value is to be synchronized worldwide,
not to agree with what an astronomer at Greenwich can measure.

--
Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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