'Gradus' definitions:

Definition of 'Gradus'

From: GCIDE

Gradus \Gra"dus\, n. [From L. gradus ad Parnassum a step to Parnassus.] A dictionary of prosody, designed as an aid in writing Greek or Latin poetry. [1913 Webster]
He set to work . . . without gradus or other help. --T. Hughes. [1913 Webster]