The term REGISTER COMPARTMENT is composed of two words, TENS and ONES. TENS is a four-letter word meaning 'a group or unit of ten, ' while ONES is a four-letter word meaning 'a single unit or thing.' Together, these two words refer to the compartments in a cash register where coins and bills are stored. The TENS compartment is used for storing coins, while the ONES compartment is used for storing bills.