urban dictionary

noun: urban dictionary
an electronic resource that lists English slang words (typically in alphabetical order) and gives their meaning, often also providing information about pronunciation, origin, and usage.

"Whenever I hear a word I aint ever hear before, I look it up on urban dictionary and find it"
"Damn, urban dictionary is up to date. It even got words that just became hype yesterday."
"Word on the streets don't exist in Oxford or Merriam Webster; you gotta look em up on urban dictionary"