Platform shoe
From wipipedia.org
A platform shoe is a shoe with a very thick sole or platform, maybe up to 3 in or 8 cm. There are also platform boots.
Shoes for fetish wear sometimes have platforms so that the heels can be very long. It is much easier walking with a 6 in heel if the sole is 3 in thick so the difference is only 3 in.
Alternatively, particularly with boots, the heel and sole may be continuous, as in the picture.
