"...why do we have loose-forwards and scrum-halfs, whilst you have lock-forwards and halfbacks?"
Then there's the 'loose head' prop and other things like open side and blind side - not to be confused with thethird man and being caught in the gully.
I can only speak of the Australian positions. Although, I always thought that 'stand-off' was simply the the first position
standing off from the scrum. The Lock forward was where I often ended up and basically we had to lock the scrum in place and keep it straight, or screw it around depending on the circumstance.
I always imagined that the field when set in perfect position, would have the halfback behind (back) the scrum midway (half) on the field of positions.
The winger is widest offcourse.
The centres are half way between the wing the half. The two wingers + the twocentres take up three quarters of the backline (4out of 6), hence the threequarters.
The five eighth is inside the centres - that is, from the wing to the half he is 5/8 of the way in-field.
Anyone who knows better, please have a go. I can speak the language but have little idea of its origins...