Question

Question for french language: "Idole" est un nom féminin, alors pourquoi dit-on "mon idole" si "mon" est masculin?

"Idole" is a feminine noun, so why do we say "mon idole" is "mon" is masculine?

Answer 1

Certain adjectives have special forms when the immediately following word begins with a vowel or has a vowel sound.
For example, instead of saying
sa idée, which would be difficult to pronounce and does not sound clearly ("cacophonie" in French), we would say son idée instead, even though the noun is feminine.
Same is true for ma/mon, ta/ton, sa/son,
also in the case of masculin nouns
ce document, but cet adverbe, cet homme, etc.
See
http://french.about.com/cs/grammar/a/specialadjforms.htm
for more examples and detailed information.