A vocabulary notebook or a set of flashcards used to learn words; students write words with meanings/example sentences for review.
毎日新しい単語を10個、単語帳に書き込んで復習している。
I write ten new words into my vocabulary notebook every day and review them.
単語帳アプリならスキマ時間に効率よく単語を覚えられる。
With a vocabulary notebook app, you can efficiently learn words in spare moments.
試験前は単語帳を繰り返し見るのが効果的だ。
Before exams it's effective to repeatedly go through your vocabulary notebook.