The Bitcoin halving is an event that cuts the reward miners receive for confirming blocks in half, roughly every four years.
The halving is programmed into Bitcoin's code to control the supply, gradually slowing the rate at which new Bitcoin is created.
Because the reward halves over time, the total supply approaches 21 million and new issuance slows until it eventually stops.
Halvings reduce the supply of new Bitcoin entering the market, and historically they have been followed by periods of rising prices, though past performance is not a guarantee.
Halvings occur every 210,000 blocks, and the schedule is known years in advance, making them predictable events.
The halving is a key part of Bitcoin's design that enforces its scarcity over time.