1) Vacuum tube component 2) Vacuum tube feature 
A dynode is an electrode in a vacuum tube that serves as an electron multiplier through secondary emission. The first tube to incorporate a dynode was the dynatron, an ancestor of the magnetron, which used a single dynode. Photomultiplier and video camera tubes generally include a series of dynodes, each at a more positive electrical potential tha...
(from the article `mass spectrometry`) ...principle of the multiplier is, as the name suggests, a multiplication of the number of electrons emerging from an electrode as compared with the ... ...has a second component that multiplies the number of electrons by a factor of typically 105 or 106. The electron multiplication takes place alo...
the anodes which are used to amplify the signal in photomultiplier tubes.
secondary-emission electrode placed and operated relative to other electrodes so that the number of secondary electrons leaving its surface exceeds the number of primary electrons incident upon ita secondary-emission electrode so placed and operated relative to other electrodes that the number of secondary electrons leaving its surface exceeds the number of primary electrons incident upon it
an electrode for the emission of secondary electrons in a vacuum tube.