Dollar cost averaging (DCA) is an investment strategy that proposes periodic and timely acquisitions of a given amount of Bitcoin or stocks. A simple example is buying $10 worth of BTC on a weekly basis, irrespective of the current market price.
This strategy prevents you from investing all your money in one lump sump - commonly referred to as Lump Sum investing. DCA comes in handy when market prices drop as you can purchase more stock or a higher amount of Bitcoin, thus putting you ahead of the pack when prices rise.
Dollar cost averaging is one of the strongest pillars of every longterm investor.