A phone number is a set of digits assigned to a phone line that enables communication through calling and texting. There are various synonyms for 'phone number,' including contact number, mobile number, cell number, telephone number, and digits, among others. A contact number refers to any number used for reaching out to a contact. A mobile number is a phone number for a mobile device. A cell number is a short form of the mobile number that is typically used by Americans. The term telephone number generally refers to any number used for phone communication, whether it is a landline or a mobile number. The word 'digits' is a more general term that encompasses any numeric characters that make up a phone number.