Vocabulary

I was checking out the vocabulary words for my fifth graders for next week. Each week they have about 6 or 7 words, but every 5th reading story there is usually 10 words. One of the words for this coming story is prognostication. Now, I am all for building the vocabulary of students, but come on are they serious???? I didn't even know what this word meant. What really irked me was that another word for the same week was flop. You would think they could at least be consistent on the level of words. I don't get it? Do you?