Let's start by defining the two words:
Bibliography or Works Cited:
"a list of materials (as books, magazines or journal articles) used in the preparation of a written work or mentioned in a text" (Merriam-Webster's Dictionary, 2015).
A bibliography is also referred to as a Works Cited or a References list.
Annotate:
"to add notes or comments to (a text, book, drawing, etc.)" (Merriam-Webster's Dictionary, 2016).
Annotated Bibliography or Works Cited:
A list of of Works Cited or References followed by a short summary and analysis of the source.
Works Cited
"Annotate." Merriam-Webster, www.merriam-webster.com/dictionary/bibliography. Accessed 31 Oct. 2016.
"Bibliography." Merriam-Webster, www.merriam-webster.com/dictionary/annotate. Accessed 31 Oct. 2016.