The term 'Bases' Counterparts' refers to the relationship between bases and ACIDS. Bases are substances that have a pH greater than 7, while ACIDS have a pH lower than 7. ACIDS are the counterparts of bases, meaning that when one is present, the other must also be present in order to maintain balance. The crossword solution for this term is 'ACIDS, ' which refers to the group of compounds that have a pH lower than 7.