The term 'pastoral sound' refers to a type of sound that is associated with rural areas and the countryside. This sound is often characterized by the sounds of animals, such as sheep, cows, and birds. The crossword solutions for this term are BAA (3 letters), NEIGH (5 letters), and MOO (3 letters). These words are all onomatopoeic, meaning they imitate the sounds of the animals they represent. BAA is the sound of a sheep, NEIGH is the sound of a horse, and MOO is the sound of a cow. Together, these three sounds create a pastoral soundscape that is often associated with rural areas.