A
person who
illuminates works of
art,
literature,
architecture,
etc, by explaining their
context,
history, and points of particular
interest.
Some critics even become philosophers for their knowledge, understanding, and ability to use language to unearth obscure recesses of knowledge.
Others, are only notable for their ability to develop words that even Webster 1913 doesn't know, or at least, only knows some small portion of them.