A surname or family name is a name added to a given name. In many cases, a surname is a family name and many dictionaries define "surname" as a synonym of "family name". In the western hemisphere, it is commonly synonymous with last name because it is usually placed at the end of a person's given name.
In most Spanish-speaking and Portuguese-speaking countries, two or more last names (or surnames) may be used. In China, Hungary, Japan, Korea, Madagascar, Taiwan, Vietnam, and parts of India, the family name is placed before a person's given name.
The style of having both a family name (surname) and a given name (forename) is far from universal. In many countries, it is common for ordinary people to have only one name or mononym.
The concept of a "surname" is a relatively recent historical development, evolving from a medieval naming practice called a "byname". Based on an individual's occupation or area of residence, a byname would be used in situations where more than one person had the same name.
Janáček is a Czech surname. Notable people with the surname include:
Janáček is a crater on Mercury. It has a diameter of 47 kilometers. Its name was adopted by the International Astronomical Union in 1985. Janáček is named for the Czech composer Leoš Janáček, who lived from 1854 to 1928. The MESSENGER Mercury orbiter crashed near the crater on April 30, 2015.