Full canonicals

the complete costume of an officiating clergyman or ecclesiastic.

See also: Canonicals

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in classic literature ?
The king sat under a canopy of state; about him were clustered a large body of the clergy in full canonicals. Conspicu- ous, both for location and personal outfit, stood Marinel, a hermit of the quack-doctor species, to introduce the sick.