The term 'PACK UP' can be broken down into three crossword solutions: CRATE (5 letters), ENCASE (6 letters), and DECAMP (6 letters). 'CRATE' is a noun that refers to a large, usually wooden box with slatted sides, used for storage or shipping. 'ENCASE' is a verb meaning to enclose something in a protective covering. 'DECAMP' is a verb meaning to leave a place suddenly and hurriedly. Together, these three words describe the action of packing up and leaving a place quickly and securely.