Definitions for "Triode"
a thermionic vacuum tube having three electrodes; fluctuations of the charge on the grid control the flow from cathode to anode which making amplification possible
an electronic amplifying valve with three main electrodes ( anode , cathode and grid)
a power amplifier as well as a voltage amplifier
a voltage source, with low plate impedance, so its gain is less affected by the load than that of a pentode, which is a current source, as is a transistor
Keywords:  good, example
a good example