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viola 
  n  (=instrument) alto  m  
I play the viola.  Je joue de l'alto. 


viola player 
  n altiste  mf 

violaceous   a violacé

Collaborative Dictionary     English-French
viola da gamba n. la viole de gambe Reverso General Dictionary 
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'viola' also found in translations in French-English dictionary
alto n. 1) viola (m), 2) alto (f) Reverso General Dictionary 

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