Service (music)
In the Tudor and early Stuart periods, services were described as "Short", "Great" or "Verse" services.  Short services were short, the words were only sung once and it was often unaccompanied (no organ).  A Great service was longer: some of the words were often sung many times.  William Byrd wrote a famous Great Service.  A Verse service was also long: there were several verses which need to be sung by a solo choir member.  In between each verse there is some music for the whole choir to sing.