What does Handheld mean?
A handheld is any portable device that can be carried and held in one's palm. A handheld can be any computing or electronic device that is compact and portable enough to be held and used in one or both hands. A handheld may contain cellular communication, but this category can also include other computing devices.
Techopedia explains Handheld
A handheld is primarily designed to provide a suite of computing, communication and informational tools in a device about the size of standard palm. Typically, handheld devices are not as powerful as a computer, but modern handhelds increasingly include powerful dual-core processors, RAM, SD storage capacity, an operating system, and native and add-on applications. They are often powered by a dry cell lithium or similar battery. Moreover, these types of devices increasingly use a touch screen interface.
Personal digital assistants (PDA), tablet PCs and portable media players are all considered handheld devices.