Slippers literally mean footwear that can be slipped on. Slippers are lightweight footwear meant for indoors though decorative slippers are worn outdoors too. Flip-flops are extremely popular outdoor footwear in many countries as they are comfortable, airy, cheap, and come in attractive patterns and colors. Traditionally, the basic purpose of wearing slippers inside the house was to demarcate hygienic indoor areas from unhygienic outdoors.

Shape and material of slippers

Slippers are shaped like a shoe or half shoe with the heel removed. This allows the wearer to slip the foot into the slipper easily. The sole of the slipper can have a strap or thin thong running between the big toe and second toe (flip-flop style) or over the toes and instep. Slippers have inner linings made of wool, suede, velour, fleece or down for warmth.

Rubber flip-flops are made of polyurethane that is not recyclable in small amounts. Many manufacturers use recycled tires and inner tubes to minimize environmental pollution. Costlier slippers are made of leather, terry cloth, cotton, coconut, and hemp.

Types of slippers

Slippers are manufactured in many designs and colors and some styles are more popular in certain countries. The main types of slippers are:

• Clogs: Japan has a tradition of removing street shoes before entering a house. Foreigners can wear special slippers called clogs that slip over the shoe.
• Toilet slippers: These slippers are meant to be worn on wet bathroom floors. The main idea is to prevent contamination (from the 'unclean' toilet floor) of other parts of the house.
• Flip-flops: Flip-flops typically have a thin rubber or plastic sole with a thong running through the first and second toe around the side of the foot. The ankle is not supported. They are worn as beachwear in some countries, but are regular wear in countries such as India, New Zealand, Pacific Islands, Southeast Asia, USA, and Brazil.
• Children slippers: Slippers come with a variety of cartoon characters and animals sewn onto them to attract children. Some slippers are even shaped like cars, frogs, ladybugs, pigs, and other favorites of kids. Children slippers can be animal slippers, oversized slippers, fuzzy slippers and cuffed slippers.
• Mules and scuffs: Mules and scuffs are open toed and of soft material. Mules come in high heels too.
• Moccasins: Moccasins come with fleece or wool linings for added comfort and warmth. They have a heel so stay on better than mules.
• Slipper socks: Socks have slipper soles sewn into them to make slipper socks. They are supplied to military personnel to use as protective footwear in case of damage to their boots.
• Boot style slippers: Boot style slippers need to be pulled on but offer extra warmth and protection.

House slippers and flip-flops are worn across the globe and have many regional names such as 'Havaii chappal' in India and Pakistan, 'thongs' in Australia and Canada, 'Go-aheads' in South Pacific,  'slip-slops' in South Africa, 'ojotas' in Spain, 'chinelos' in Brazil, and 'katkafim' in Israel. Depending on the material they are made of, prices of slippers vary from less than a dollar to a few hundreds.