The crossword solution for the term 'Celtic, for one' is 'cager, ' which is an acronym for 'college athlete.' Cager is a term used to refer to college athletes who compete in sports such as basketball, football, and soccer. It is derived from the word 'CAGE, ' which is a reference to the court or field on which these athletes compete. The term is most commonly used in the United States, but it is also used in other countries.