"The Steel Curtain"
And they lived up to it -- Mean Joe Greene, Ernie Holmes, L.C. Greenwood and Dwight White. That is the Steel Curtain.
A lot of people get confused and think the whole Steelers' defense of the 1970s was the Steel Curtain, but it wasn't. It was that defensive line's nickname.
It is also the best nickname because the team's real nickname is inside it.