A lockup unit is a secure facility used to detain people who have been arrested or are awaiting trial. It is typically staffed by correctional officers and is designed to keep inmates safe and secure. The term 'lockup unit' can also refer to a specific type of CELL, which is a four-letter word. Cells are small, enclosed spaces that are used to house inmates in a lockup unit. They are typically made of metal or concrete and are designed to be secure and provide minimal comfort.