Websites
www.etymonline.com (Type the word and its parts in the search bar)
www.wordinfo.info (Type the word and its parts in the search bar)
http://www.awrsd.org (List of Greek and Latin Root words)
Tips:
Look up the word exactly how it is written.
See if you can break the word down into its root, prefix, suffix.
Look up the separate root.
Look up the prefix.
Look up the suffix.
*The websites listed here are only meant to start you off. There are literally thousands of websites, books, and other resources you can consult to find information about every single word in the English language. I strongly encourage you to make it a habit of looking up roots, prefixes, and suffixes in addition to whatever is required for a grade. We need words to convey our thoughts in this world. Plus, it can be fun to see how words take on new meanings with time!