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1.
iPx
Any of Apple's devices whose name begins with the two letter sequence, "iP," i.e. an iPhone, iPad, or iPod (Touch).

Generally iPx is used to avoid specifying which particular device a person or group of people are using.
If the person is talking about communication between iPx devices the reference would exclude all iPods except the iPod Touch because the other iPods can not access the World Wide Web directly.
Plural is either "iPxs" or "iPxes."
The wife and I are not going to travel this Christmas, but we'll video chat with everyone because we all have at least one iPx.
The grand parents on their iPxes will get to see the little ones open presents in real time.
by Captain Smokeblower December 16, 2011