Sometimes semantics are telling.
Most of the time, talking about cellular devices, I use terms like "handset", "mobile phone", "phone", or "cellphone". Maybe "device" when I want generically to include PDAs or data cards as well.
But almost every time I speak to someone involved in cellular networks , either from an infrastructure vendor or operator, they typically use the word "terminal". Almost nobody else does.
I think this is a bit of legacy, and reminds me of this philosophy. It highlights the traditional "centralised" telecoms operator way of thinking, and ignores the implications of Moore's Law on the "smartness" of handsets and their resident applications and growing capabilities.
Another manifestation of this is the backward philosophy is the notion that services should "work seamlessly across different access technologies", with the network trying to create an illusion of a lowest common denominator. Instead, I believe that handsets should pay close attention to "seams" and modify their own behaviour and optimise for the pecularities of different networks. I'll post more on this specific issue later, as I see it as a fundamental flaw in IMS.