Bedding, also known as bedclothes or bed linen, is the materials laid above the mattress of a bed for hygiene, warmth, protection of the mattress, and decorative effect. Bedding is the removable and washable portion of a human sleeping environment. Multiple sets of bedding for each bed will often be washed in rotation and/or changed seasonally to improve sleep comfort at varying room temperatures. In American English, the word bedding generally does not include the mattress, bed frame, or bed base (such as box-spring), while in British English it does. In Australian, South African and New Zealand English, bedding is often called manchester.