By most definitions, characters do not require actual superhuman powers or phenomena to be deemed superheroes. While the Dictionary.com definition of "superhero" is "a figure, especially in a comic strip or cartoon, endowed with superhuman powers and usually portrayed as fighting evil or crime", the longstanding Merriam-Webster dictionary gives the definition as "a fictional hero having extraordinary or superhuman powers; also: an exceptionally skillful or successful person". Terms such as masked crime fighters, costumed adventurers or masked vigilantes are sometimes used to refer to characters such as the Spirit, who may not be explicitly referred to as superheroes but nevertheless share similar traits.
Halloween costumes are costumes worn on or around Halloween, a festival which falls on October 31. An early reference to wearing costumes at Halloween comes from Scotland in 1585, but they may pre-date this. There are many references to the custom during the 18th and 19th centuries in the Celtic countries of Scotland, Ireland, Mann and Wales. It has been suggested that the custom comes from the Celtic festivals of Samhain and Calan Gaeaf, or from the practise of "souling" during the Christian observance of Allhallowtide. Wearing costumes and mumming has long been associated with festivals at other times of the year, such as on Christmas. Halloween costumes are traditionally based on frightening supernatural or folkloric beings. However, by the 1930s costumes based on characters in mass media such as film, literature, and radio were popular. Halloween costumes have tended to be worn mainly by young people, but since the mid-20th century they have been increasingly worn by adults also.