A Dictionary of Music and Musicians/High Mass
HIGH MASS (Lat. Missa Solemnis; Fr. Grand-messe; Germ. Grosse Messe). Mass, sung throughout, with full Ceremonial, the Priest being assisted by Deacon and Subdeacon, Master of Ceremonies, Thurifer and two Acolyths. A Mass, sung with equally solemn music, but without the assistance of a Deacon and Subdeacon, and without the use of Incense, is called a Missa cantata, or Sung Mass.
Low Mass is said by the Priest, without music, and with the assistance of one Server only. [See Mass.][ W. S. R. ]