humeral veil

Eccles. a long, narrow piece of cloth, usually of silk, worn over the shoulders and covering the hands as of a priest holding the monstrance at Benediction

See humeral veil in American Heritage Dictionary 4

noun
Roman Catholic Church
A vestment resembling a shawl worn over the shoulders by a subdeacon during High Mass and by a priest when holding the monstrance.
link/cite print suggestion box