In American music a Semibreve is called a "whole note". Here it states that the name "whole note" comes from a German expression (ganze Note):
In the world of music, you may encounter different names for the many notes used. The U.S. and U.K. standard terms differ, but the U.S. names — which were originally translated from the German names for the notes because so many German composers immigrated to the United States in the 19th century — are more universally standard. The U.K. names are also used in medieval music and in some classical circles
Source: http://www.dummies.com/art-center/music/music-theory-for-dummies-cheat-sheet/
=> Is it a German invention that a Semibreve is taken as a reference value and called "whole note"? Who is the inventor of this terminology?
It causes some logical problems in time signatures other than 4/4.
=> Why don't we call a Crotchet a "whole note"?
Also see http://www.studybass.com/using-the-site/american-english-music-terminology/