I think there's a website for that More on reddit.com

It depends on what you want it for. These days, nothing can beat the websites: oed.com for the historical dictionary (which lists all the things a word has ever meant since its first appearance in English, so if you look up 'nice' the first thing you'll find is 'foolish, silly, simple, ignorant' because that is the oldest meaning) or premium.oxforddictionaries.com for the current dictionary. They contain all the latest information and discoveries and no book can measure up (if the current OED were printed, it would be twice the size of the 2nd edition of the OED, which took up 20 sizeable tomes). However, if you want a book, the Oxford Dictionary of English is your best bet for finding the meanings of words: https://www.oxfordreference.com/display/10.1093/acref/9780199571123.001.0001/acref-9780199571123 This dictionary lists what words mean now. The Concise Oxford English Dictionary is a much abbreviated version of the historical dictionary, which will give you historical information as well as the meanings. The Compact Oxford English Dictionary is an amazing artefact but not something you will want if you want to actually look up words: it's a huge book that contains the full 2nd edition of the Oxford English Dictionary with 9 pages printed to a page and a magnifying glass to be able to read it. Amazing in the day - it allowed people who couldn't afford a 20-volume set to own the full thing - but not really worth the effort now. The Compact Dictionary of Current English is basically the Oxford Dictionary of English, but smaller. More on reddit.com

There is no single best or most complete or most authoritative dictionary or dictionary website, and it's best if you don't rely on just one, because dictionaries have different purposes or philosophies and will differ in how they present senses or nuances. Also, general purpose dictionaries are aimed at native speakers, and may provide definitions that seem circular or overly complex to a learner. To that point, I recommend using OneLook , which links you directly to entries from several different dictionary websites. For learners, I recommend Oxford OALD , Macmillan , Cambridge CALD , Longman , or Merriam-Webster MWLD (especially for American usage). Collins COBUILD is also popular, but I personally don't like the way they present the material. The Cambridge Dictionary and Collins Dictionary websites can be useful because they search multiple dictionaries at once, although in my experience (including on this sub), this has served to confuse learners as much as it helps them. For general purpose dictionaries, Lexico (formerly Oxford Living Dictionaries) and Cambridge are reliable for British uses and Merriam-Webster and the American Heritage Dictionary for American uses. AHD is more linguistically conservative than MW. If you are dealing with historical texts and want something truly comprehensive, the most authoritative resource is the Oxford English Dictionary (not just any English dictionary published by Oxford, but the work known as the OED). This is a historical dictionary that attempts to catalog all meanings that all words have ever had since the dawn of the English language itself, including senses that may not have been used in hundreds of years. It is structured very, very differently from general purpose dictionaries and not intended for everyday use, but it is fascinating to read through some of the entries. More on reddit.com

Much of the second edition is available for short-term loan on Archive.org with free registration: https://archive.org/search.php?query=%22oxford%20english%20dictionary%22%20simpson&sort=date More on reddit.com