highlighter

noun

1. A marker pen used to highlight text.
2. A cosmetic product that reflects light, used to emphasize the contours of the face etc.
3. That which highlights or emphasizes something.

   “The IPL was supposed to be a symbol of an ever-more influential, dynamic and prosperous India, a highlighter of its organizational skills and wealth.”

   “At the same time, art rooted in nature is eminently ephemeral, as human life itself is, and fairy lore again operates as a highlighter of this essential condition through its own distinctive world picture[…]”