Cross-referencing words in crosswords is a technique used by constructors to create more interesting puzzles. It involves placing words that are related to each other in the same puzzle, either in the same row or column. The term 'cross-referencing word' is used to describe a word that is related to another word in the same puzzle. This technique can be used to add complexity and difficulty to a crossword, as it requires the solver to think about the relationship between the words in order to solve the puzzle.