Ask HN: Why do daily crossword puzzles repeat their words?
Is there a good reason for doing this?
For some more practical reasons, in some styles of British crosswords, there isn't much intersection between words. A horizontal word might cross only 2-3 vertical words. In the standard US crossword, though, there are a lot of intersections. Almost every letter in a horizontal word has to be part of a vertical word as well.
In this context, there are certain patterns that come up a lot but are hard to find words for. A few words that have a nice structure for crossword writers show up with high frequency: acai, ogre, etc. Words or acronyms with several letters that rarely occur together are also useful for getting the crossword writer out of a jam.