What Is a Halving? | Cryptocurrency Glossary

Mining rewards continue to halve

Bitcoin is obtained as a reward through mining, and the system is designed so that new Bitcoins are issued through this process.
This reward is not fixed but is designed to gradually halve.
In other words, the "halving" in Bitcoin refers to the point in time when the mining reward is cut in half.

When Bitcoin was first created, the mining reward was 50 BTC per block. As for
when the halving occurs, the reward is set to be reduced to half of the previous reward every time 210,000 blocks are mined.

The 210,000th block, marking the first Bitcoin halving, was reached on November 29, 2012, at which point the mining reward for that block was halved to 25 BTC.
The second halving will occur upon the generation of the 420,000th block, at which time the mining reward will be 12.5 BTC.

This process will repeat itself. If we start with a reward of 50 BTC and halve it every 210,000 blocks, calculations show that the 6,929,999th block will be the last to receive a mining reward. Since
Bitcoin is designed so that a new block is generated approximately once every 10 minutes, it is estimated that the final block to receive a mining reward will be reached around the year 2140.