Part V: Regional & Cultural · Casino Slang & Historical Terms
6.13 Lock
Slang — Betting
A “lock” is a bet that a gambler believes is certain to win. The term is used with heavy irony in professional gambling circles, as there is no such thing as a guaranteed outcome in games of chance. “Giving a lock” means providing a betting tip with supposed certainty. Experienced gamblers and casino professionals understand that calling any bet a “lock” demonstrates either ignorance or hubris.
In practice
The concept of a “lock” is frequently exploited by touts and tipsters who sell betting picks to unsophisticated gamblers. Casino surveillance teams are trained to recognize when individuals are selling locks or running betting scams on property.
More in Slang — Betting
One entry from the Casino Industry Glossary — 1,157 terms written for surveillance, compliance and operations professionals rather than for players. Definitions describe industry usage; where a term carries a regulatory meaning, verify against the instrument that governs your jurisdiction.