One of the many ways to spell the word that sounds like 'word'. There are many different meanings and each meaning has a different spelling. The word w3rd refers to the 'that was dope' side of the meaning. When someone does something cool one would reply with 'w3rd'. Similar words would be 'werd', 'whurd', 'wird', 'ward', 'whard', etc. There are many different words, and they all have specific meanings.
Guy one: Shizzle my nizzle my brother. That was stupid fresh, don't you think?
Guy two: W3rd!
Guy four: Thanks guys!