Dollar-cost averaging, often shortened to DCA, describes the practice of investing a fixed amount at regular intervals, rather than putting in a large sum all at once. For example, someone might set aside the same amount each month regardless of the current price.
The idea behind it is to reduce the impact of short-term price swings. Because purchases are spread out, some happen when prices are higher and some when they are lower, which averages out the entry price over time. This can make volatility feel less stressful than trying to pick a single moment.
DCA is a concept, not a recommendation or a guarantee of any result. It is described here so you understand a term you will often encounter. As with anything involving money, whether it suits someone depends on their own goals, circumstances, and risk tolerance.