It contains two words. One begins with P. Neither word is simply "a," or "portable."

It's a man-made mass produced electronic device, and there is more than one of it. It does not occur in nature. It has parts which move. Its construction involves metal (among other things), but no liquids. It is not a component of a larger object. It does not involve superconductivity. It was invented (as a whole item) some time after 1980, although the basic principles it uses were known long before that (that's a new hint). It usually includes a clock of some sort, and would contain a computer program within it.

It is not primarily for entertainment, nor is it connected with writing. It's nothing to do with hygiene.

It is connected with travel, but not flying or vehicles. You would take it on certain travels. It is not required for travelling abroad, nor is it specific to road travel.

It is not a frisbee, a buzzer, a pylon, a parking meter, a mobile phone, a container, a GPS navigation system, a digital camera, a data projector, a conduit, fancy car keys, a biometric passport, or a credit card.