Originally Posted by John Bean
Blowing aside the iPhone chaff (it uses a different numbering system) and considering only the current "Nexus x" models (where "x" is a number) then the "x" is an indicator of the screen size - not exact of course, but 4.-something in the case of the Nexus 4. Similarly the Nexus 7, Nexus 10 relate to the screen size of each device.
Perhaps Google will change its mind and start to use the number as a generation indicator like Apple does with the iPhone, but the new Nexus 7 (still 7, note) tells me that this is unlikely unless the screen size changes.
There again some marketing droid may decide that the existing screen is near enough 5" to call it a Nexus 5 anyway without changing a thing. We'll have to wait and see :-)
Actually, though admittedly nit picking, only
Tablets have had numbering reflecting screen size, while, as pointed out, the phones never have. I'm guessing that if the Nexus 5 is "Nexus 5," it will be a generational number even if it has a 5" screen.
They will no doubt have to name the Nexus generation 7 phone to avoid confusion.
Nexus 5, 32 GB,Rooted, Dirty Unicorns v7 Official, Android 4.4.2, Build KVT49L, Franco Kernel, Nova Launcher.
Nexus 7 (2012) wifi+data (AT&T), Slimkat Build 4, Android 4.4.2, Build KVT49L, Franco Kernel, Art, Nova Launcher.