Duolingo

noun4

1. •
   (informal) A language learning service or application.
2. •
   (informal) A website, service or application that gamifies or simplifies learning, such as through having convenient, guided lessons and an informal (laidback) educational environment.

   • Melodics, the music practice app that’s been described as the Duolingo of music learning, is now available on iPad for all subscribers. — 2019
3. •
   (Internet, informal) A lesson on Duolingo.

   • I DIDN'T DO MY DAILY DUOLINGO YDAY. S H I T — 2015
4. •
   (informal, rare) A language learning course on Duolingo.

   • Is doing two Duolingos at once, say Spanish and Russian, a bad idea?