ˌkäməˌshu̇ˈräd.əmē, -_shəˈr- noun
( -es )
Etymology: International Scientific Vocabulary commissure + -o- + -tomy
: the operation of cutting through a band of muscle or nerve fibers ; specifically : separation of the flaps of a mitral valve by cutting or by use of a finger to relieve mitral stenosis — compare finger fracture , valvulotomy