Ambiguous whether is it mangos or mangoes. dictionary.com is no help. The definitive resource is as well, although I did not know that mango also has represented "In Ireland: a substance used in the bleaching of linen" nor "A dealer in slaves, esp. in prostitutes". So I turn to google and the web for help.
No help here (freshmangos.com). Title of their front page: "A Mango Web Site. All about mangos featuring mangoe recipes. Fresh mangoes for your health". I'm not making that up.