A learned vocab item is a term that you know. In this program, a vocab item is considered learned when you have successfully practiced it in at least one activity which requires you to produce the learning language word or phrase, such as Produce & Say It or Produce & Write It. Alternatively, you can mark an entire lesson as learned if you know all of its vocab items from other sources.
Learned vocab items can be fresh or stale, depending on when they were last practiced. They can also be archived when you don't want to practice them anymore.