original_query: What are the main variations in the use of the three terms in different institutions?
query: What are the main variations in the use of the terms JCR, MCR, and SCR in different institutions?
answer: Variations include terminology (e.g., combination room), the inclusion of mature and postgraduate students in JCRs, MCRs, or SCRs, and whether the terms refer to an actual room or just an association of students/academics.