In some casinos, the rule that placing chips equal to or greater than half the normal bet amount beyond the amount required to call constitutes a commitment to raise the normal amount. For example, in a game with a $4 fixed limit, a player facing a $4 opening bet who places $6 in the pot is deemed to have raised, and must complete his bet to $8. Compare to "full bet rule". See Public cardroom rules (poker) and "all in" betting.
  

The following video provides you with the correct English pronunciation of the word "half bet rule", to help you become a better English speaker.