It’s constantly evolving alongside the cultures that use them—and slang frequently showcases this complex relationship at its most creative, playful, and strange. While some terms or phrases may linger for centuries, most of today’s slang terminology is more current. The culmination was Green’s Dictionary of Slang, a three-volume reference set containing 10.3 million words over 53,000 separate entries. Today, an original copy of Green’s Dictionary can easily set you back over $1,300. As Open Culture recently highlighted, Green’s Dictionary of Slang is now available for free as its own, regularly updated website.