According to lexicographer Jesse Sheidlower, the principal American editor of the Oxford English Dictionary, the terms hipster and hippie derive from the word hip, whose origins remain unknown. The words "hip" and "hep" first surfaced around the beginning of the 20th century and spread quickly, making their first appearance in the Oxford English Dictionary in 1904. At the time, the words were used to mean "aware" and "in the know"