A canter, or lope is a three beat gait. The footfall pattern when circling to the right should be left hind, right hindleg, left fore (almost at the same time), right foreleg . When circling right, the right legs will be reaching further forward. As these legs contact the ground they push the horse forward and there is a moment of suspension.
On a right lead the right foreleg reaches further than the left. This is called a 'right lead'. The left lead is mirror to the right lead. On a left circle the left legs will reach forward further. The lead is easiest to see by watching the forelegs.
It is desirable to have the horse on the correct lead for the circle as this helps with balance. Riding a circle on the wrong lead intentionally is called a 'counter canter'.
Pronunciation: l ee d
The horse lost its balance and stumbled in the barrel race because it was on the wrong lead.