Semiconductor Abbreviation KV

I can't recall seeing this sort of thing for silicon wafers. Warp, particulates, parallelism, doping-resistivity&uniformity, dislocation, growth type, size, orientation, flat (orientation&size). But not blunt length, or KV3. Could you be talking about butterfly valves ("wafer valves")?

Or can you provide some sort of reference?

Fyz