The term 'Fairy Tale Word' is composed of two crossword solutions, 'ONCE' and 'UPON'. 'ONCE' is a word that is used to refer to a single occurrence or event, while 'UPON' is a preposition that is used to indicate a position above or over something else. Both words are commonly used in fairy tales, which often feature characters who experience a single event or encounter a situation that is above or over them.