gum [ME] In the sense ‘a sticky secretion produced by some trees and shrubs’, gum can be traced all the way back to an ancient Egyptian word kemai. Among its more recent meanings it has been applied to a type of sweet pastille (as in ‘fruit gum’) since the early 19th century, and to chewing gum from the mid 19th century in the US. The other type of gum, inside your mouth, comes from an Old English word meaning ‘the inside of the mouth or throat’. Gumshoe is an American term for a detective. Dating from the early 20th century, it relates to rubber-soled shoes, called gumshoes or sneakers, suitable for doing something stealthily.