At home alone; especially (of a child) left at home unsupervised during parental absence.
In later use popularized by the title of the U.S. film Home Alone (1990), in which a young boy is accidentally left at home when the rest of his family go on holiday.
Designating a person (especially a child) who is at home by himself or herself; relating to a situation in which a person is at home alone.
Late 19th century; earliest use found in The New York Times. From home + alone.