We don't have synonyms for control grid yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are control rod.
(n) :
An electrode used in amplifying thermionic valves (vacuum tubes) such as the triode, tetrode and pentode, used to control the flow of electrons from the cathode to the anode. It usually consists of a cylindrical screen or helix of fine wire surrounding the cathode, and is surrounded in turn by the anode.
(n) :
An electrode used in amplifying thermionic valves (vacuum tubes) such as the triode, tetrode and pentode, used to control the flow of electrons from the cathode to the anode. It usually consists of a cylindrical screen or helix of fine wire surrounding the cathode, and is surrounded in turn by the anode.