What does 'terms that are compatible with the GPL' mean?

[B. Lee]

>From Octave's FAQ(http://wiki.octave.org/FAQ#Licensing_issues),


Code written using Octave's native plug-in interface (also known as a
.oct file) necessarily links with Octave internals and is considered a
derivative work of Octave and therefore must be released under terms
that are compatible with the GPL.

...

A program that embeds the Octave interpreter (e.g., by calling the
"octave_main" function), or that calls functions from Octave's
libraries (e.g., liboctinterp, liboctave, or libcruft) is considered a
derivative work of Octave and therefore must be released under terms
that are compatible with the GPL.


Here, 'terms that are compatible with the GPL' appears repeatedly.

At first, I thought that it can be any license in the list of
GPL-compatible license
here:https://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses

However, the part of '... is considered a derivative work of Octave
and therefore must be released under terms that are compatible with
the GPL' makes me confusing.

As far as I know, derivative work of GPLed one should follow GPL
itself not compatible one.

What are 'terms that are compatible with the GPL', here?