DVOL is Deribit's implied volatility index, computed from the BTC and ETH options books in much the same way VIX is computed from SPX. It expresses the market's expectation of volatility over the next 30 days, annualised, in percentage points.
The division that makes it useful
An annualised volatility figure divided by roughly 20 gives you the expected daily move, because there are about 252 trading days in a year and the square root of 252 is close to 16 - and crypto, trading every day, is closer to 20. So DVOL 40 implies about a 2% daily move. DVOL 80 implies 4%.
That is a genuinely practical number. It sets the width you should expect a range to hold, tells you whether a 3% move is remarkable or routine, and gives you an expected-move band without needing to price a straddle.
Level versus term structure
The absolute level tells you less than its shape. When near-dated implied volatility sits above far-dated - backwardation - the market is pricing something soon. Contango, the normal state, means the near term is calm relative to the horizon.
Skew is the other half. Comparing near-the-money put and call implied volatility says which side is being bid. Take that comparison across the whole strike ladder and you measure wing convexity instead, where implied volatility is legitimately 100%+ and tells you nothing about directional demand.
DVOL covers BTC and ETH only; no altcoin has a deep enough options book to support an index. The Crypto Market Map shows DVOL, the implied daily move and near-the-money skew for both.