I agree that it is acceptable but, as I'm sure you noticed, your dictionary definition comes from the American Heritage Dictionary and my point was that whilst it is used in America, it is not a term or phrase that an English person would use. Not least because we don't have a space program, whereas the only time I've actually heard the phrase is in Hollywood movies about NASA or the military.
No Mr Micawber, I mean English as spoken and written in England, hence why it is called English not British. I believe the alternative is Standard English, and the Scots speak Gaellic, the Welsh speak Welsh and the Irish speak Celtic.
England invented English hence it is called English. It is the original not a derivative and therefore needs no further differnetiaition.
I would have thought that you would comprehend that English is the language of England, not Britain nor the United Kingdom. If the latter applied the language would be called British or United Kingdomesque!
Scotland, Wales and Northern Ireland all have their own tongues. Welsh is once again commonly taught in schools in Wales and my own grandmother spoke Welsh fluent