ONLINE DICTIONARY: but take it with a grain of salt. It gives you EVERY possible form of a word, and you have to have discretion to understand which one is accurate...
https://logeion.uchicago.edu/%CE%BB%CE%BF%CE%B3%CE%B5%E1%BF%96%CE%BF%CE%BD
You could also download the app "Whitaker's Words" onto your phone -- it's a Latin to English AND English to Latin source.
Students should study from the below vocabulary packet all year. Every week there will be a quiz on apx. 30 words.
As derivatives remain EC, this may interest you: https://latinisenglish.files.wordpress.com/2008/03/latin-derivatives-a-to-v.pdf
57 Reading Notes
56 Reading Notes
55 Reading Notes
Reference Materials