Definitions for "Socket A"
200 MHz AMD Duron, no longer manufactured.
AMD's 462-pin CPU interface form factor which replaced Slot A at the time of the introduction of the Thunderbird and Spitfire cores used by AMD's Athlon and Duron desktop processor ranges respectively.
Most AMD Athlon and Duron processors require a motherboard with a Socket A. This socket is how the processor is "plugged into" the motherboard.