A flush toilet, also known as a flush lavatory or water closet, is a plumbing fixture used for the disposal of human waste.

Hand washing (or handwashing), also known as hand hygiene, is the act of cleaning one's hands with soap or handwash and water to remove viruses/bacteria/microorganisms, dirt, grease, and other harmful or unwanted substances stuck to the hands.

An improved water source (or improved drinking-water source or improved water supply) is a term used to categorize certain types or levels of water supply for monitoring purposes.

A sanitary sewer is an underground pipe or tunnel system for transporting sewage from houses and commercial buildings (but not stormwater) to a sewage treatment plant or disposal.

Sanitation refers to the safe disposal of waste and the maintenance of clean and hygienic conditions.

Sustainable sanitation is a sanitation system designed to meet certain criteria and to work well over the long-term.

UNICEF is an acronym for the United Nations International Children's Emergency Fund.

The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health.