Peacock stirrups are stirrups which have a rubber or leather band on the outside, designed to give under pressure. They are often used when teaching young children how to ride, as they significantly reduce the risk of catching a foot in the stirrup and getting dragged. A lot of people think they look awful, but they are a good safety device. (Older children often refuse to use them).
(Note, western people do not use peacock stirrups but do sometimes use breakaway stirrups of a different design).