scholiast
noun
scho·li·ast ˈskō-lē-ˌast 
-lē-əst
: a maker of scholia : commentator, annotator
scholiastic
ˌskō-lē-ˈa-stik
adjective 
Word History
Etymology
Middle Greek scholiastēs, from scholiazein to write scholia on, from Greek scholion
First Known Use
1565, in the meaning defined above