Was there ever a legal decision in the US regarding the word
Montessori (name of the Italian educator) that placed it in the public
domain?  If so, what was this decision and how can I reference it?

Please note that as a researcher for Google Answers, I cannot provide
an expert legal opinion; I can only provide the results of my
research.  If you need a professional opinion about this matter, you
should consult a lawyer who specializes in intellectual property law
(trademark, patents, and copyright).

It appears that there has not been a need for a legal decision
regarding whether the name "Montessori" is in the public domain in the
United States, because the name "Montessori" (or "Montessori Method")
was and is not registered as a trademark in the U.S. (except with
respect to a brand of clothing and a computer program, not a school or
a general teaching method).  However, several names containing the
word "Montessori" have been registered as a trademark in the U.S. 
(The fact that several people have been able to use the word
"Montessori" in their names itself indicates that the name is in the
public domain.)  You can obtain the list of these names from the
United States Trademark and Patent Office (USPTO) by clicking on
"Trademark Electronic Search System (TESS)" at the upper-left corner
of the following page, then clicking on New User Form Search (Basic),
and finally, searching for "montessori":

"Trademark Information"
United States Trademark and Patent Office
http://www.uspto.gov/web/menu/tm.html

(I am unable to include a link to the results here, because TESS seems
to treat each search as unique, so that a link to the search results
would not work.)

Also, it appears Maria Montessori received at least two patents for
inventions, in July 1914 (Patent No. 1103369) and February 1916
(Patent No. 1173298).  These patents are referred to in several
subsequent patent applications in the following list:

"USPTO Patent Full-Text and Image Database: Results of Search in All
Years db for: montessori: 17 patents"
United States Trademark and Patent Office
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2Fsearch-adv.htm&r=0&p=1&f=S&l=50&Query=montessori%0D%0A&d=pall

But your interest is in the Montessori name, not in inventions by
Montessori. The USPTO and United States Copyright Office explain that
names may be protected by trademark, not by patent or copyright.

"Basic Facts About Trademarks" (Last Modified: 10/16/2001)
United States Trademark and Patent Office
http://www.uspto.gov/web/offices/tac/doc/basic/trade_defin.htm

"Frequently Asked Questions About Trademarks: How do I find out if I
need patent, trademark and/or copyright protection?"
United States Trademark and Patent Office
http://www.uspto.gov/web/offices/tac/tmfaq.htm#Patent001

"Frequently Asked Questions about Copyright: Can I copyright the name
of my band?"
United States Copyright Office
http://www.copyright.gov/faq.html#q43

So, to sum up, it appears that the name "Montessori" itself has not
been protected by trademark (nor by patent or copyright), though names
including the word "Montessori" have been.  That appears to be the
legal status of the name "Montessori", speaking, of course, as a
researcher and not an expert lawyer.

I hope that this information is helpful.

- justaskscott-ga


Search strategy:

Searched on Google for:
montessori trademark
montessori trademarked
montessori patent
montessori patented

Found references of unknown reliability asserting that "Montessori"
was not a trademark, and that Montessori had received a patent.

Browsed the USPTO site for FAQs on the distinctions between trademark
and patent, and conducted searches on the USPTO as explained in the
text of the answer.

Thorough, fast, polite and did I say thorough?  Thanks very much --
this service is a fantastic idea.  And justaskscott-ga *rocks*.  'Nuff
said.  Thanks again.