Basically, “16” refers to the “16 Bars” slang from our previous entry. 16 is just the same as it references the measures within a rap song or references the actual verse of a rap. It may be used as such:
“Lisa’s 16s are the bomb. They have the chill vibe that I love.”
“You better start recording, dude. This 16 right here is gonna make you famous.”
This slang is very much popular among rap fans and rap creators. It is a common arsenal in their list of jargon, especially when talking about rap.