For most kids learning a language, opening a dictionary to a solid page of text with definitions that are harder than the word they are trying to learn is unhelpful and even stressful.
The Gamerize Dictionary contains an ever expanding dictionary that is ideal for language learners. Each entry has an illustration, translations, example sentences and real voice audio.
Sentences are graded carefully so that the words in the sentence are not more difficult than the target word. Illustrations are very helpful for visual learners and make it easier to retain words than just studying with translations.