I have been pondering recently (in the absence of any more interesting thoughts this morning) of the meaning of the above, which has been triggered by a recent misunderstanding of the phrase. I always thought a round of sandwiches was one whole sandwich made with two slices of bread and then cut in halves or quarters. However recently a friend asked for a round of sandwiches but only expected a single half sandwhich and was somewhat surprised when I made and presented one sandwich cut in half, as per my understanding.
But then I have always thought that a round of toast is only one slice, so perhaps I have misunderstood this for many years in the context of sandwich making. And then again buying a round in the pub means, in my mind, buying a drink for everyone in the same group ( or possibly the same circle?).
And I assume 'round' refers to the traditional loaf shape rather than square cut bread that produces triangles when cut in halfs or quarters on a diagonal line, or squares if cut vertically and horizontally across the centre line.
I'd be interested to know what others understand by this phrase?