The Collaborative International Dictionary of English v.0.48:

Scholium \Scho"li*um\, n.; pl. L. Scholia, E. Scholiums.
   [NL., fr. Gr. ?, fr. ?. See School.]
   1. A marginal annotation; an explanatory remark or comment;
      specifically, an explanatory comment on the text of a
      classic author by an early grammarian.
      [1913 Webster]

   2. A remark or observation subjoined to a demonstration or a
      train of reasoning.
      [1913 Webster]