A "Palm" is a commonly referred to as a small-scale (hand-held) computer that runs Palm's PalmOS software.
Palm Computing was founded by Jeff Hawkins, Donna Dubinsky and Ed Colligan. The original purpose of the company was to create handwriting recognition software for other devices (Graffiti). The initial idea for the devices came from Hawkins' habit of carrying a block of wood in his pocket.
The initial Palm device released in 1996 was called the Pilot. Because Pilot Pen Corporation brought forth a trademark infrigement case, the second generation device released in 1997 was named the PalmPilot.
The Palm was not the original PDA device released, but benefited from the failure of Apple's Newton.