English-French/Spanish/Italian dictionary :
http://www.wordreference.com/
German-French dictionnary :
http://dict.leo.org/?searchLoc=0&searchLocRelinked=0&lp=frde&search=&lp=frde
Grand dictionnaire terminologique
(French, English-French, French-English)
http://www.olf.gouv.qc.ca/ressources/gdt.html
Dictionnaries
I advice you to use as soon as possible a "French-French" dictionnary and particularly the Dictionnaire du français that is adapted for the people for whom French is not the tongue language.
Dictionnaire du français, Paris, Dictionnaire Le Robert-CLE International, 1999
(ISBN 209-033999-3)
and because sometime you don't even know the word in your own language, I advice you to also use a visual dictionnary :

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