viz
n.— «For divers, all that silt obscures almost everything. “I always say, gimme a foot of viz”—visibility—“and that’s a great day,” says the NYPD’s John Drzal. “Even with a light, you can see just enough to gauge how much air you have left.”» —“Secrets of the Deep” by Christopher Bonanos New York Magazine May 10, 2009. (source: Double-Tongued Dictionary)