Oxford English Dictionary
www.oed.com
The historical English dictionary An unsurpassed guide for researchers in any discipline to the meaning, history, and usage of over 500,000 words and phrases across the English-speaking world.
DICTIONARY Definition & Meaning - Merriam-Webster
www.merriam-webster.com
The meaning of DICTIONARY is a reference source in print or electronic form containing words usually alphabetically arranged along with information about their forms, pronunciations, functions, etymologies, meanings, and syntactic and idiomatic uses.