“Steelo” is a corruption of the word “style” (from the Spanish estilo); prophetically, Nas is telling us that we will all know his rap style whether or not he’s getting played on the radio (“airplay”)
At the time, Nas probably meant by this that he has an “underground” following; today, it is true because Nas is not a rapper who gets crossover hits and radio play, but the entire corpus of modern rap has sprung from his style, footprinted in the songs off Illmatic (like this one).
Fascinating coincidence: ‘stylo’, pronounced identically to ‘steelo’, translates from French as ‘pen’. The line is no less true abiding by this interpretation; Nas' pen-work could be spotted a mile off.
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