triode

UK: /ˈtraɪəʊd/ US: (trī′ōd)

WordReference Random House Unabridged Dictionary of American English © 2026

tri•ode  (trī′ōd), n. [Electronics.]

1. Electronics a vacuum tube containing three elements, usually anode, cathode, and control grid.

• tri- + (electr)ode 1920–25

Collins Concise English Dictionary © HarperCollins Publishers::

triode / ˈtraɪəʊd/ noun

1. an electronic valve having three electrodes, a cathode, an anode, and a grid, the potential of the grid controlling the flow of electrons between the cathode and anode. It has been replaced by the transistor
2. any electronic device, such as a thyratron, having three electrodes

Etymology: 20th Century: tri- + electrode