QAWG's solution
After arguing the issue for a few months...
Each GL document can have a Definitions section.
Definitions will reference, can complement, cannot contradict QA Glossary.
SpecGL
[...]
Definitions:
.. test assertion
.... See QA Glossary.
.... [+ unique SpecGL stuff]
OpsGL
[...]
Definitions:
.. test assertion
..... See QA Glossary.
..... [+ unique OpsGL stuff]
TestGL
[...]
Definitions:
.. test assertion
..... See QA Glossary.
..... [+ unique TestGL stuff]
QA Glossary