Dictionaries are often treated as the final arbiter in arguments over a word's meaning, but they are not always well suited for settling disputes. The lexicographer's role is to explain how words are (or have been) actually used, not how some may feel that they should be used, and they say nothing about the intrinsic nature of the thing named or described by a word, much less the significance it may have for individuals. When discussing concepts like racism, therefore, it is prudent to recognize that quoting from a dictionary is unlikely to either mollify or persuade the person with whom one is arguing.

https://www.merriam-webster.com/dictionary/racism