gradus
noun
gra·dus
ˈgrādəs
plural -es
1
: a dictionary of Greek or Latin prosody and poetical phrases used as an aid in the writing of verse in Greek or Latin
2
: a handbook (as of law phrases or forms) or exercise book to assist in the mastering or performance of a difficult art or practice
Word History
Etymology
from Gradus ad Parnassum (Latin, literally, a step to Parnassus), a 17th century prosody dictionary long used in British schools