There are several commonly used synonyms for the term "fax number." Some people refer to it as a "fax line" or "fax machine number." Others may use the term "fax contact" or "fax address." In some cases, it may be referred to as a "facsimile number" or simply a "fax." Regardless of the term used, it refers to the phone number associated with a fax machine or fax service. This number is used to send and receive faxes, which are electronic documents transmitted over a telephone line. Whether you call it a "fax number" or use one of the synonyms, it remains an essential tool for businesses and individuals who rely on fax communication.