We need to link to Quantum GIS on a major official website. My legal department asks me if "Quantum GIS" is trademarked. Is it?
Yes, QGIS is now trademarked, see https://www.qgis.org/en/site/getinvolved/governance/trademark/index.html for more details.
Short answer: No it is not yet trademarked.
The phrase, "Quantum GIS", is not found in the US Trademark electronic search.
Trademark status is not mentioned on the Quantum GIS website, nor is,
a trademark symbol nor statement used in the documentation.
The OSGeo website does have two trademark-related pages, but they only mention various OSGeo and FOSS trademarks.
You might check the archives of the mailing lists, particularly the project steering committee.
Their wiki discusses how to cite the software
Cite the QGIS project in general
Quantum GIS Development Team, <YEAR>. Quantum GIS Geographic Information System. Open Source Geospatial Foundation Project. http://qgis.osgeo.org
Please note: QGIS name and logo are now under trademark http://www.qgis.org/en/site/getinvolved/governance/trademark/index.html
Because I like to encourage research, however, I take your point. My research indicates that the answer can be gleaned from the documentation.
"This document is the original user guide of the described software Quantum GIS. The software and hardware described in this document are in most cases registered trademarks and are therefore subject to the legal requirements. Quantum GIS is subject to the GNU General Public License. Find more information on the Quantum GIS Homepage"