Handheld, PDA, palm-top, palm-sized device - these names are used loosely and interchangeably. But there is an important distinction: palm-sized and handheld devices are different species with different characteristics.

The term PDA has come to be a universally accepted one for both handheld and palm-sized devices.

Palm-sized
Palm-sized devices fit snugly in your palm, which inspired the name of 3Com's well-known contribution to the PDA arena: the PalmPilot.

Though they started out as electronic organizers, today's palm-sized devices offer features far beyond organization.

Unlike the larger handhelds, palm-sized PDAs don't include a keyboard. Rather, owners tap on a virtual keyboard or write with specially recognized strokes using a stylus pen.

Writing with the stylus is possible with the use of handwriting technology software, like the well-known Graffiti that comes standard on Palm's devices. Users must get used to using special one-stroke symbols that resemble English letters, which the software recognizes and then displays in normal computer font.

Palm-sized devices, also referred to as palm-tops, are easy to transport - they're tiny and ultra light, weighing only a few ounces.

In addition to tracking appointments and contacts, you can also use hardware with many palm-sized models -- like modems and MP3 players -- and install basic software on them.