Steam (steam move)
A sudden, market-wide line move driven by sharp money, which books copy within seconds to minutes.
During a steam move the books are briefly out of sync — some have moved, some have not — and that is exactly when identical-line price disagreements appear. Most sports arbitrage windows are steam moves seen from the outside, which is why they close within minutes.
Related terms: Sharp book vs soft book · Arbitrage · Closing line value