What is the definition of absolute maximum ratings?
So, short story is the definition of absolute maximum rating does vary from manufacturer to manufacturer.
Most every manufacture (of those sampled) will give a variation of this warning:

Stresses beyond those listed under Absolute Maximum Ratings may cause
permanent damage to the device.

Then proceed to tell you that this might happen over time:
Exposure to absolute maximum rating

conditions for extended periods may affect device reliability.

If international standards count for anything here is IEC60134 which &quot;standardizes&quot; the definition of absolute maximum ratings:
IEC60134 paragraph 4: Absolute maximum rating system This section states:

“Absolute maximum ratings are limiting values of operating and
environmental conditions applicable to any electronic device of a
specified type as defined by its published data, which should not be
exceeded under the worst probable conditions.
These values are chosen by the device manufacturer to provide
acceptable serviceability of the device, taking no responsibility for
equipment variations, environmental variations, and the effects of
changes in operating conditions due to variations in the
characteristics of the device under consideration and of all other
electronic devices in the equipment.”

Here is where it gets really boring, but I threw this up for comparison
Analog says that their absolute maximum ratings won't kill the part instantly but it will degrade over time:

Stresses above those listed under Absolute Maximum Ratings may cause
permanent damage to the device. This is a stress rating only;
functional operation of the device at these or any other conditions
above those indicated in the operational section of this specification
is not implied. Exposure to absolute maximum ratings for extended
periods may affect device functionality.

They also say on many of their chips its process based.

The maximum supply voltage that can be applied to an op amp is
determined by the fabrication process. It refers to the instantaneous
value, not the average or final value. Low voltage CMOS op amps from
Analog Devices, Inc., are typically limited to 6 V, whereas high
voltage bipolar parts are limited to 36 V.

Source: Analog App Note MS-2551
Linear Technology gives a standard warning and reliability:

Stresses beyond those listed under Absolute Maximum Ratings may cause
permanent damage to the device. Exposure to any Absolute Maximum
Rating condition for extended periods may affect device reliability
and lifetime.

Maxim Electronics gives the standard warning and that it will affect reliability:

Stresses beyond those listed under “Absolute Maximum Ratings” may
cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other
conditions beyond those indicated in the operational sections of the
specifications is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.

Texas Instruments is the same:

Stresses beyond those listed under absolute maximum ratings may cause
permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those indicated under recommended operating conditions is not
implied. Exposure to absolute-maximum-rated conditions for extended
periods my affect device reliability.

The exception is Rohm and they say you can't exceed the ratings ever or you'll cause damage:

Absolute maximum ratings are conditions that should never be exceeded,
even momentarily. For example, supplying a voltage over the maximum
rating and/or using in environments outside of the temperature range
may cause deterioration of IC characteristics or even damage.

Source: Rohm Absolute Maximum Ratings