Here at, we take the concept of word mastery seriously.

When you're learning a word, whether it's from a list or you're playing the Challenge, you'll see multiple questions on each meaning until we're confident that you know every sense of that word. Along the way, we expose you to examples pulled from real-world texts so that you learn each word as it's used in various contexts. continually assesses your understanding to make sure that you learn — and remember — each word inside and out.

Why is so thorough? Research shows that there is a strong relationship between depth of student word knowledge and reading comprehension success. "Comprehension involves not just reading words and knowing what they mean but how they are connected in language to make meaning." In other words, it's not just how many words you know, it's how well you know them that helps you understand them when you speak, read, listen, and think.

What does it take to master a word?  First of all, mastering a word takes time. How long? It depends. Typically, it will take you multiple sessions over multiple days before you master a word. works with you until you master the words you're learning.

Why so long? Remember — we need to make sure you really know it, by giving you multiple questions on multiple meanings of the word. Plus, we need to give you a little time to forget in between, so that we can make sure that you are retaining all the good stuff you are learning.

The amount of time it takes to master a word depends on a few factors:

  1. How many meanings a word has. We won't let you master a word until you have demonstrated understanding of all the essential definitions of the word (we might skip some really obscure meanings). You'll master the easiest definitions of a word first, then we'll move on to harder meanings later.
  2. How many questions you get right / wrong.  The more you get questions incorrect, the longer it will take to master a word.  Get every question right?  We may decide that you know the word and should master it more quickly.
  3. How many other words you're learning at the same time.  If you choose to learn a lot of words (either by electing to learn them individually, or by choosing to "Learn this List" on a number of lists), it might take you longer to master them because we have to spread the time you are dedicating to mastery over a large number of words.

Once I master a word, will I ever see it again? You bet. We want to make sure that you hold on to all of your heard-earned word knowledge, so we'll work with you to retain what you've learned. Once you master a word, we'll periodically give you "brush-up" questions on that word just to make sure you're not getting rusty.  The more you struggled with a word initially, the more often you'll see brush-up questions.  Once we're thoroughly convinced that you know a word and won't forget it, we'll ease up and you may never see a question on that word again.

It's useful to remember that the power of word knowledge is not derived solely from the sheer number of words we know, but also from the richness of that knowledge. Knowing words well — multiple definitions in varied contexts — is essential to understanding words whenever and wherever we encounter them. Depth is as important as breadth when it comes to word learning, and that is why works with you to achieve word mastery.