Dictionaries are TERTIARY SOURCES. Dictionaries provide meaning and pronunciation, for words and phrases. Specialized dictionaries can also provide background and contextual information on people, places, events, and subjects.
Tertiary sources should be used to familiarize yourself with a topic and lead you to important primary and secondary sources, making them an important part of your research process.
However, unless approved by your instructor, avoid quoting tertiary sources due to their lack of indepth information.