LTC being similar to BTC, A Litecoin halving is an event where the number of generated Litecoin rewards per block is halved. Occurring roughly every four years.
What's interesting is that when I did an analysis on LTC, the chart suggests that the price of LTC tends to hit the top around 600 days before the halving occurs, which would be by the end of 2021, aligns with my Bitcoin analysis.