SmaTan スマ単 is a free Android app developed by PENTEL CO.LTD. It falls under the category of Education & Reference and provides users with a digital vocabulary notebook that combines the benefits of handwriting and digital technology. With SmaTan スマ単, users can learn new vocabulary words without having to carry a physical notebook.

The app uses a dedicated notebook called "SmaTan" where users can write English words on the left page and their Japanese translations on the right page. By taking a picture of the open notebook, the app generates 12 cards at once. Users can tap the screen to reveal the answer and sort the cards into green and red categories for efficient and effective studying. SmaTan スマ単 is a great app for those looking to learn new vocabulary words in a fun and efficient way.