(n) bandmaster
(n) Treaty of Portsmouth (ending the Russo-Japanese War, 1905)
(n) postmaster
(n) mass culture
(n) mascarpone
(n) unequal pressure between the mask air space and the vascular pressure within the blood vessels of the face
(n) (game) development deadline (wasei: master up)
(n) master course
(n) master code
(n) master tape
(n) (comp) master data
(n) mustard gas
(n) masterpiece
(n) master plan
(n) (comp) master page
(n) masterwork
(n) (comp) master drive
(n) must-have (wasei: must item)
essential item
(n) litmus paper
(n) (comp) anonymous ftp
(n) (comp) anonymous server
(n) Christmas card
(P)
(n) Christmas carol
(n) Christmas cake
(n) Christmas tree
(P)
(n) Christmas wreath
(n) Christmas rose (Helleborus niger)
(n) (comp) content master
(n) (comp) subnet mask
(n) Tibetan mastiff (dog breed)