Here at, we take the concept of word mastery seriously. Which means that when you're playing the Challenge, we don't stop sending you questions on a word until you're comfortable with every sense of its meaning, in multiple, often confusing context environments pulled from real-world texts.

Why are we so thorough? As we were recently reminded by a recent study by vocabulary education researchers on the 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 always how many words you know, it's how well you know the ones you do that helps you understand them when you speak, read, listen, and think. 

This study used benchmarks of morphological, semantic, and syntactic knowledge to describe word depth, testing students' knowledge of word parts, multiple word meanings, and the ways that words functioned within language. The study's authors explain: 

A student who has depth of word knowledge for the word aware that one sits at a table, but in reading a science text or conducting an experiment, one also creates, reads, and/or interprets a table. Further, while table is a noun, its morphological derivation, tabulate, is a verb, and is thus used in a grammatically and syntactically different context. Thus, in order to create a table, one must tabulate relevant data, perhaps while seated at the dinner table. Far less attention has been paid to the investigation of this type of vocabulary depth, its contribution to reading comprehension, and how that relationship is relevant for instruction.

(A quick tour of table's definition page in the Dictionary shows how the learning resources on the page promote morphological, semantic, and syntactic understanding. For more on these resources, check out this short video introduction to our Dictionary here.) 

For vocabulary learners, it can be useful to stop and remember from time to time that the power of word knowledge does not always come from the sheer number of words we know, but from the richness of that knowledge. So keep playing the Challenge and rest assured that when the progress bar turns from green to gold for mastery, you have achieved bonafide depth of knowledge on that word.