Pastoral, n.
1. A poem describing the life and manners of shepherds; a poem in which the speakers assume the character of shepherds; an idyl; a bucolic. A pastoral is a poem in which any action or passion is represented by its effects on a country life. Rambler.
2. (Mus.)
A cantata relating to rural life; a composition for instruments characterized by simplicity and sweetness; a lyrical composition the subject of which is taken from rural life. Moore (Encyc. of Music).
3. (Eccl.)
1 more senses
A letter of a pastor to his charge; specifically, a letter addressed by a bishop to his diocese; also (Prot. Epis. Ch.), a letter of the House of Bishops, to be read in each parish.
1 other Webster entry under this spelling
Pastoral, a.
1. Of or pertaining to shepherds; hence, relating to rural life and scenes; as, a pastoral life.
2. Relating to the care of souls, or to the pastor of a church; as, pastoral duties; a pastoral letter. Pastoral staff (Eccl.), a staff, usually of the form of a shepherd's crook, borne as an official emblem by a bishop, abbot, abbess, or other prelate privileged to carry it. See Crook, and Crosier. -- Pastoral Theology, that part of theology which treats of the duties of pastors.
Shades of meaning
Fernald has no entry of its own for pastoral; he lists it under rustic.
Where he writes about it:
Pastoral refers to the care of flocks, and to the shepherd's life with the pleasing associations suggested by the old poetic ideal of that life; as, pastoral poetry. — from rustic
Bucolic is kindred to pastoral, but is a less elevated term, and sometimes slightly contemptuous. — from rustic