How I Use It
Depending on the situation, I created or found good vocabulary lists to use with my students. There are TONS of vocabulary lists already made tailored to specific novels or topics. Teachers and individuals can create their own lists as well to build resources that are shared.
I gave my students links to the lists and let them decide how to study. There are multiple ways in which students can study words rather than simply memorise definition. I encourage them to download the app as well so that they can practice in those in-between times.
Very few people LOVE studying new vocabulary words, so vocabulary.com does the wondrous job of making it a bit more fun and a lot more efficient. Creating lists and sharing them makes teacher work way more effective as well.
When I was teaching The Giver, for example, I found a great, thorough list that pulled words directly from the novel. It deepened understanding of the book for all students.
For those students needing greater challenge, there are advanced lists. I have had students use lists to help them prepare for applying to private schools (SSAT lists). For students who are new to English, you can offer them high frequency word lists so that they can build basic comprehension more quickly.
Again, vocabulary learning is not glamorous, but it's a big part of building literacy. Vocabulary.com makes that task quite a bit better.