The Collaborative International Dictionary of English v.0.48:

Macoun \Ma*coun"\ (m[.a]*k[=oo]n"), prop. n.
   A juicy, late-ripening apple similar to a McIntosh.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

Macoun
    n 1: similar to McIntosh; juicy and late-ripening