The term 'doubly' is used to describe something that is TWOFOLD or TWICE as much. It can be expressed in four letters as 'DUAL', seven letters as 'TWOFOLD', or five letters as 'TWICE'. This term is often used to describe a situation where something is done or experienced TWICE, such as a doubly-enjoyable experience or a doubly-difficult task. It can also be used to describe something that is TWOFOLD in nature, such as a doubly-edged sword or a doubly-charged particle.