The terms “citation,” “reference,” and “bibliography” have some overlap, but there are nuances in their definitions and in how they are used in different styles.

Citation is the most common term used to refer to in-text documentation of sources, such as parenthetical citations in APA, MLA, or Chicago author-date style. These in-text citations typically give only partial information about a source (such as author and date). The term citation can also refer to the full source information given in a footnote or a reference list, works cited, or bibliography entry.
Reference is often used interchangeably with citation, although the term reference is more likely to be used to refer to the full source information given at the end of a document rather than a parenthetical citation. In APA Style, the full list of sources at the end of the document is known as the reference list and has the title “References.”
Bibliography always refers to a full list of sources used or consulted in a work. It is used with Chicago notes and bibliography style and sometimes with other styles as well.