According to
Dictionary.com, both usages are correct.
Quote:
noun, plural anthologies.
1. a book or other collection of selected writings by various authors, usually in the same literary form, of the same period, or on the same subject:
an anthology of Elizabethan drama; an anthology of modern philosophy.
2. a collection of selected writings by one author.
|
I've always used it to refer to a collection with some sort of unifying theme, which could be a single author, a single genre, a common year of publication, etc.