tetanus diphtheria and acellular pertussis vaccine (n)~ A vaccine for immunization against tetanus-diphtheria-pertussis. The term acellular means that the pertussis component is cell-free which improves safety by reducing the incidence of side effects. tethering ~ enables your cellular telephone or similar Internet-enabled mobile device to connect other devices such as netbooks laptops or PDAs to the Internet. Mobile phones that offer tethering typically connect to other devices via Bluetooth or a USB cable in order to provide them with Internet access.