(chiefly historical) An electronic device incorporating electrons from a glowing cathode inside an evacuated glass tube, functioning as a switch, amplifier etc.

The genesis of osteosarcomata

(nautical, historical) A flat-bottomed barge used on shallow shores to convey cargo to and from ships that cannot enter the harbour.

A main road or highway, especially in ancient Rome. (Mainly used in set phrases, below.) / (electronics) A small hole in a printed circuit board filled with metal which connects two or more layers.