We use Quizlet in 2nd grade for vocabulary word practice on a weekly basis.
Quizlet would work for any grade level for practice and repetition.
How I Use It
I think this is a great App for vocabulary word practice. Students log in and find the teacher's username. Each week I type their Robust Vocabulary words into the template with definitions and they are able to practice 3 different ways. The program has an audio component so ear buds are a must.