Dollar Cost Average

What Does Dollar-Cost Averaging - DCA Mean?
The technique of buying a fixed dollar amount of a particular investment on a regular schedule, regardless of the share price. More shares are purchased when prices are low, and fewer shares are bought when prices are high. Also referred to as a "constant dollar plan".

For example, you decide to purchase $100 worth of stock AJ each month for three months. In January, AJ is worth $20, so you can buy 5 shares. In February, AJ is worth $25, so you buy 4 additional shares this time. Finally, in March, AJ is worth $10, so you buy 10 shares. In total, you purchased 19 shares of AJ for an average price of approximately $16 each.

In the U.K., it is known as "pound-cost averaging".