Wickets are typically small, narrow doors either alongside or within a larger castle or city gate. The latter were often double gates, large and heavy, designed to allow the passage of wagons, coaches and horsemen. The purpose of wickets was to avoid the risk of having to open the main gates to the castle or city for just one or two individuals on foot. Because the wicket was only one person wide, it only allowed entry one at a time and enabled the guards to better control access.
A wicket gate is also used for a stand-alone gate that provides convenient secondary access, for example to the rear of a walled park or garden.