The term 'arrangement in folds' can be defined as the process of arranging fabric into pleats or folds. This term is often used in the context of DRAPERY, which is the art of creating and hanging curtains, drapes, and other window treatments. The crossword solution for this term is 'DRAPERY, ' which is a seven-letter word. DRAPERY is a type of fabric that is often used to create window treatments, such as curtains, drapes, and valances.