«Magret» is not "duck breast"

Question

For "breast" in breast of duck, the exercise uses "magret". Can you explain why? LaRousse defines "magret" as "Fillet of duck fattened for the production of foie gras.", which does not seem to be the same thing, as clearly not all ducks are forced fed to make foie gras; and clearly it would be redundant to say «de canard»

I used blanc, which seems a lot closer: «Partie charnue d'une volaille qui tient à la carcasse.» but is not accepted.

https://www.larousse.fr/dictionnaires/francais/magret/48627

https://www.larousse.fr/dictionnaires/francais/blanc/9729

Accepted Answer

Larousse definition is incomplete in this case. 
I can assure you that “magret de canard” is most certainly what duck breast fillets are known, sold and eaten as in France. 
Have had them prepared for me many times by my French in-laws.
Searching recipes or cooking sites is a good way to check things like this. 
The first link will work, I hope. It is from a French cooking site I subscribe to. 
Note recipes by the renowned Alain Ducasse for ‘Magret de canard’ - duck breast: 
https://www.academiedugout.fr/#q=Magret&query=Magret&type=&categoryId=&tagId=&authorId=&media=&difficulty= 
https://everydayfrenchchef.com/?s=Magret 
https://dictionnaire.lerobert.com/definition/magret