Pill, is Cb slang for a transistor, typically a Toshiba 2SC2879 , but it could also be a sd1446, 2sc2290 etc.
So....
A "two pill" would be a Amp with 2, 2879`s in it.
A "four pill" would be a Amp with 4, 2879`s in it, and so on
A 1x4 would be 1 transistor driving 4 transistors.
With out getting into a very large dispute about power output, and to put it in simple terms.......
As a "general rule of thumb" a 2sc2879 is a 100/120 watt output device @ nominal 12.5 volts DC.
For example, The Ameritron ALS 500M uses 4, 2sc2879 transistors and is rated at 500 Watts PEP and 400 watts CW.
The Texas Star 500V uses the same 4 transistors and is generally seen as being capable of approx 500/600 watts PEP.
This all depends on supply voltage, input drive and the device used to measure the output.
73
Jeff