Fax

• fax
• 1 [countable] a letter or message that is sent in electronic form down a telephone line and then printed using a special machine:
• Did you get my fax?
• 2 [countable] also fax machine a machine used for sending and receiving faxes:
• What's your fax number?
• 3 [uncountable] the system of sending letters and messages using a fax machine
• by fax
• You can book tickets by fax or on-line.

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.