Look for the publisher and printing information within the first few pages of the book.
Take note of the author (if applicable), edition number, year published and publisher location.
Understand the layout of citation. The APA citation would be: Author. Published work (Edition). (Year). Publisher location: Publisher. Mosby's Medical Dictionary does not have a specified author, so the author would be omitted from the rest of the citation.
Write the title of the dictionary followed by the edition, abbreviated and in parentheses, and a period:
Mosby's medical dictionary (7th ed.).
Note that only the first word and names in the title are capitalized using APA citation.
Write the publication year of the particular dictionary you are using in parentheses. For example, the seventh edition was published in 2005 and would be written as such:
Mosby's Medical Dictionary (7th ed.). (2005).
Write the location of the publisher followed by a colon and the publisher's name:
Mosby's Medical Dictionary (7th ed.). (2005). St. Louis, MO: Mosby.