Firebottle: N. A Large, Primitive, Power-hungry Active Electrical
Device, Similar In Function To A FET But Constructed Out Of Glass,
Metal, And Vacuum.
:firebottle: n. A large, primitive, power-hungry active electrical
device, similar in function to a FET but constructed out of glass,
metal, and vacuum. Characterized by high cost, low density, low
reliability, high-temperature operation, and high power
dissipation. Sometimes mistakenly called a `tube' in the U.S.
or a `valve' in England; another hackish term is {glassfet}.
-- The AI Hackers Dictionary