Growth stocks are loosely defined as those with higher-than-average earnings growth rates, although the precise definition of a growth stock can vary. Investors choose growth stocks because of their potential for market-beating returns, and it's not hard to see why. After all, investors who bought shares of growth stocks Netflix and Tesla just five years ago are currently sitting on gains of 892% and 459%, respectively. The downside is that growth stocks tend to be more volatile, and therefore more risky, than value stocks.

One solution to this problem is to diversify your growth stock investments by purchasing an exchange-traded fund that invests in hundreds of different fast-growing companies. There are growth ETFs to fit any growth investor's risk tolerance and investment goals, so here are seven great choices to help you start your search, followed by a brief discussion of each one.

When searching for the best growth ETFs, I look for a few different things. First, there are several types of growth funds -- for example, they may focus on large-, medium-, or smaller-sized companies. Many growth ETFs focus on U.S. I also look for a reasonably low expense ratio. If you aren't familiar, an ETF's expense ratio is the annual investment fee shareholders pay, expressed as a percentage of the fund's assets.

When it comes to index funds, I generally want to see expense ratios of 0.25% or less, although there are some exceptions. For example, international ETFs tend to have slightly higher-than-average expense ratios. Image source: Getty Images. Data Source: TD Ameritrade. As the name implies, the iShares Russell 1000 Growth ETF tracks the Russell 1000 Growth Index, which is an index of large- and mid-cap stocks.

Specifically, the Russell 1000 index consists of the 1,000 largest companies in the Russell 3000 index, which is widely thought of as an excellent total-stock market index, as it contains companies of all industries, in a wide variety of sizes. Within the Russell 1000 Index there are both growth and value stocks, and the Russell 1000 Growth ETF focuses on the 552 stocks that exhibit "growth characteristics," based on the stock's price-to-book ratio, medium-term growth forecast, and historical growth rates.

As with most indexes, the Russell 1000 Growth Index's components are weighted by market capitalization, meaning that stocks with larger market caps have a bigger effect on the index's performance. For example, even though the ETF owns 552 stocks, nearly 6.6% of its assets are invested in Apple, because the company has the world's greatest market cap. In a nutshell, the iShares Russell 1000 Growth ETF is a good choice for investors who want broad exposure to larger growth stocks in their portfolio.

It allows investors to focus on the largest U.S. 6, so you get to keep more of the returns of the underlying investments. The fund tracks the CRSP U.S. Large Cap Growth Index, which consists of 300 of the largest growth stocks in the U.S. Because of this, it should come as no surprise that the fund's top holdings look quite similar to those of the Russell 1000 Growth ETF.

So who should invest in the Vanguard Growth ETF, Simply put, it's a good choice for investors who want low fees and diverse exposure to large growth stocks without leaving too much of their portfolio tied to a single company's fortunes. Generally speaking, growth stocks don't pay high dividends. In a nutshell, fast-growing companies typically feel that the best use of their profits is to invest them back into the business. It's rare to find a growth stock with a dividend yield above 3% or so.

However, there are some solid dividend-paying growth stocks, and the Vanguard Dividend Appreciation ETF focuses on these companies. The ETF tracks the NASDAQ US Dividend Achievers Select Index, which consists of 182 stocks with strong track records of raising their dividends. With a 1.87% dividend yield, the ETF isn't exactly "high income," but it can certainly be a good compromise for investors who want exposure to exciting growth stocks but also rely on their portfolio for income.

Plus, the dividends paid by the fund tend to rise over time. In fact, it currently pays a 41% higher dividend than it did 10 years ago. The Russell 3000 is an index of small, medium, and large U.S. The Russell 2000 is made up of the smallest 2,000 components of the Russell 3000, and it's widely considered to be the best small-cap benchmark of the U.S. The iShares Russell 2000 Growth ETF invests in the Russell 2000's growth stocks -- 1,186 of them, to be exact.