A top hat, beaver hat, high hat silk hat, cylinder hat, chimney pot hat or stove pipe hat (sometimes also known by the nickname "topper") is a tall, flat-crowned, broad-brimmed hat

Hat

A hat is a head covering. It can be worn for protection against the elements, for ceremonial or religious reasons, for safety, or as a fashion accessory. In the past, hats were an indicator of social status...

, predominantly worn from the latter part of the 18th to the middle of the 20th century. Now, it is usually worn only with morning dress

Morning dress

Morning dress is the daytime formal dress code, consisting chiefly for men of a morning coat, waistcoat, and striped trousers, and an appropriate dress for women...

 or white tie

White tie

White tie is the most formal evening dress code in Western fashion. It is worn to ceremonial occasions such as state dinners in some countries, as well as to very formal balls and evening weddings...

, in dressage, as servants' or doormen's livery

Livery

A livery is a uniform, insignia or symbol adorning, in a non-military context, a person, an object or a vehicle that denotes a relationship between the wearer of the livery and an individual or corporate body. Often, elements of the heraldry relating to the individual or corporate body feature in...

, or as a fashion statement.
The top hat is sometimes associated with the upper class

Upper class

In social science, the "upper class" is the group of people at the top of a social hierarchy. Members of an upper class may have great power over the allocation of resources and governmental policy in their area.- Historical meaning :...

, becoming a target for satirists and social critics.