I was taught musical theory in the UK where I grew up. I was taught what a bar is. In my experience, the terminology "measure" is not used in a musical sense in the UK.
Since living in the US, I have generally found that "measure" is a direct synonym for "bar". However I hear some people here use both terms, which has confused me.
In the US, are the terms "bar" and "measure" exactly equivalent, or is there some subtle distinction between the two?