Legate, n.
Etymology: [OE. legal, L. legatus, fr. legare to sent with a commission or charge, to depute, fr. lex, legis, law: cf. F. légat, It. legato. See Legal.]
1. An ambassador or envoy.
2. An ecclesiastic representing the pope and invested with the authority of the Holy See.
Note: Legates are of three kinds: (a) Legates a latere, now always cardinals. They are called ordinary or extraordinary legates, the former governing provinces, and the latter class being sent to foreign countries on extraordinary occasions. (b) Legati missi, who correspond to the ambassadors of temporal governments. (c) Legati nati, or legates by virtue of their office, as the archbishops of Salzburg and Prague.
3. (Rom. Hist.) (a) An official assistant given to a general or to the governor of a province. (b) Under the emperors, a governor sent to a province.
Shades of meaning
Fernald has no entry of its own for legate; he lists it under delegate.
Where he writes about it:
The legate is an ecclesiastical officer representing the Pope. — from delegate