"Steve Foley" wrote in message
...

In much the same way that flying VFR over a layer of clouds is VFR on top,
no matter how much the pack howls.


From the Pilot/Controller Glossary:

VFR-ON-TOP - ATC authorization for an IFR aircraft to operate in VFR
conditions at any appropriate VFR altitude (as specified in 14 CFR and as
restricted by ATC). A pilot receiving this authorization must comply with
the VFR visibility, distance from cloud criteria, and the minimum IFR
altitudes specified in 14 CFR Part 91. The use of this term does not relieve
controllers of their responsibility to separate aircraft in Class B and
Class C airspace or TRSAs as required by FAAO 7110.65.


From FAR Part 1:

1.1 General definitions.

IFR over-the-top, with respect to the operation of aircraft, means the
operation of an aircraft over-the-top on an IFR flight plan when cleared by
air traffic control to maintain "VFR conditions" or "VFR conditions on top".

VFR over-the-top, with respect to the operation of aircraft, means the
operation of an aircraft over-the-top under VFR when it is not being
operated on an IFR flight plan.