The one way to settle an argument over a word is to "look in a dictionary" or we "look a word up in a dictionary". If we want to be very serious, we consult a "dictionary". There are several ways in which "compilers" of "dictionaries" or makers of a "dictionary" can approach their task. One way is to make it "descriptive" where you simply "define" it or you can be "prescriptive" when you comment on its correct use.
One of the best-known compilers of a "dictionary" was the Scottish philologist, James Augustus Henry Murray who is famous for having laid the foundations of what is known as the "Oxford English Dictionary". Someone who creates a "dictionary" is called a "lexicographer". It was a long process and although he lived till he was 78, Murray did not see the completion of the work he started. The plan had been to finish the "dictionary" in 10 years but it actually took 70 and was first published in 10 volumes in 1928. Murray put an advertisement in a newspaper and asked members of the public to send him lists of words with details of where they found them. Thousands of pieces of paper were kept in his garden shed which he called the "scriptorum". Murray later met one of his most regular contributors and discovered that he was an American murderer who had been writing to him from a lunatic asylum in Britain.
The "Oxford English Dictionary" is based on what are called historical principles so that apart from finding the meaning of a word "definition" you can also see when and where it was first used. Mind you if you keep on telling everyone how much you know about words, you could expect this comment: "What's the matter with you? Have you swallowed a dictionary?"