If your text includes a word's definition from an online dictionary, your reference list citation should include the name of the source as well as the retrieval information for the entry. Unlike most American Psychological Association style citations, dictionaries do not require author information. Therefore, your in-text citation should include the name of the dictionary along with the date.
Reference List Citation
Your reference list is a separate page after the body of your text that acts as a collection of all the sources you cite. To cite an online dictionary in your reference list, you will need the name (word you are defining) and URL of the definition you're citing, the year the web page was updated and the name of the dictionary. Arrange this information as follows:
Definition title. (Year). Name of dictionary. Retrieved from URL
See the following example:
Coffee. (2015). Dictionary.com. Retrieved from http://dictionary.reference.com/browse/coffee?s=t
You are also required to cite an online dictionary definition in the text of your paper. Your in-text citation for an online dictionary entry should include the dictionary name and the year the web page was updated. Your in-text citation might look like this:
Coffee can be made either as a "decoction or an infusion" (Dictionary.com, 2015).