1) Scholar 2) Scholarly person 3) Student 
commentator; writer of marginal notes
• (n.) A maker of scholia; a commentator or annotator.
Scho'li·ast noun [ Greek ..., from ... a scholium: confer French scoliate . See Scholium .] A maker of scholia; a commentator or annotator. « No . . . quotations from Talmudists and scholiasts . . . ever marred the effect of his grave temperate discourses.» Macaula...
[n] - a scholar who writes explanatory notes on an author (especially an ancient commentator on a classical author)
scholiast 1. A medieval scholar who wrote commentaries on ancient Greek and Latin texts. 2. One of the ancient commentators who annotated the classical authors.
noun a scholar who writes explanatory notes on an author (especially an ancient commentator on a classical author)