You're probably right, and we're sorry about that. We compiled the lists for Prefix/Suffix of the Day by hand, so we definitely missed a bunch of words that should be in those lists (unlike the dictionary of which words are playable, which we're pretty confident in). Please email email@example.com a list of words that we're mishandling so that we can improve our Prefix/Suffix of the Day lists.
Some notes on which words count for Prefix/Suffix of the Day
- Our goal with Prefix/Suffix of the Day is to help learners of English develop a practical understanding of the language. E.g., we'd like a player who isn't very good at English to learn that TRI- often means "three", so that when they see the word TRICYCLE they'll realize that it might mean a cycle with three of something.
- We aren't interested in teaching etymology for its own sake. One example is the word TRIVIA. TRIVIA has roots in a word related to "three", but most modern users don't associate "three" with the word TRIVIA. So we intentionally left TRIVIA off the list of words that relate to the TRI- prefix.
- This "practical understanding" argument also led us to include a few words that have a meaning aligned with the Prefix/Suffix of the Day even though their meanings aren't etymologically related to the prefix/suffix.