In popular use, “a” bibliography is a list of sources used in a paper or book. This would include articles, chapters in books, and entire books. There are also what are known as “subject bibliographies” which are often monographs (books) listing sources on that subject. E.g., A subject bibliography of the Second World War : books in English, 1975-1983, by A. G. S. Enser (1985). This is also known as an “enumerative bibliography” which is a compendium of sources in particular field of study, World War II in this case. An annotated bibliography is a list of sources with “annotations” which are usually brief descriptions listed with each item. An enumerative bibliography can also be an annotated bibliography.
Bibliography as a discipline is indeed the study and systematic description of books including authorship, how the item was printed, the physical properties of the book (e.g., what type of paper used), as well as analysis of variations of publications including what are known as variations and editions. In my library school’s Analytical Bibliography class we were taught that a new edition occurred when more than twenty percent of the type (letters) in a book have been reset, or changed. If less than twenty percent of the type has been reset, the new item is called a “variation.”