BJL,
I've never come across a reference to the Olympus 4/3rds system as a 'cropped format'. However, I don't spend much time on other photographic forums. Maybe you do and see a problem here.
I'm all in favour of greater precision in our expressions and don't really have a problem specifying precise dimensions except when the actual dimension vary by some small degree from the oft quoted dimensions. My mind then usually switches off. For example, the image size of 6x4.5 film is actually slightly smaller, but I'm blowed if I can remember by how much.
As for the smaller P&S formats, the appellations used might all be precisely defined, but who can remember what the precise dimensions are? In fact, there'd be a lot of P&S owners who wouldn't have a clue as to the size of their sensor, either in terms of height and width or in terms of that archaic terminology such as 1/2.5" or 1/2.7".
There'd be a lot of people also who would not know that the 35mm format is precisely 24x36mm, but I'd be surprised if they were at all confused by the term itself, either 35mm or full frame 35mm.