The Collaborative International Dictionary of English v.0.48:

Lamaism \La"ma*ism\, n.
   A modified form of Buddhism which prevails in Tibet,
   Mongolia, and some adjacent parts of Asia; -- so called from
   the name of its priests. See 2d Lama.
   [1913 Webster] Lamaist

WordNet (r) 3.0 (2006):

Lamaism
    n 1: a Buddhist doctrine that includes elements from India that
         are not Buddhist and elements of preexisting shamanism
         [syn: Lamaism, Tibetan Buddhism]