The term 'KIND OF RAT' can be broken down into three crossword solutions: GYM (3 letters), RINK (4 letters), and SEWER (5 letters). GYM is an abbreviation for the word 'GYMNASIUM, ' which is a large room or building used for sports, exercise, or other physical activities. RINK is an abbreviation for the word 'rinkrat, ' which is a slang term for a person who spends a lot of time at a roller skating RINK. Finally, SEWER is an abbreviation for the word 'SEWER rat, ' which is a type of rat that lives in sewers and other underground areas. All three of these terms refer to different kinds of rats, each with their own unique characteristics.