Sure, stocks don't pay interest. I just looked up the word "compound" in a couple of dictionaries and the relevant definition in all of them just mentioned interest and not growth in the value of stock. So it may be technically inaccurate to talk about "compound growth" of a stock. I'll yield to someone more knowledgeable about the technical language of finance to answer that part.
But regardless of whether the word strictly applies, the concept certainly does. Suppose you put $1000 into a mutual fund and the fund grows by 10%. You now have $1100. The next year the fund grows by 15%. So you gain 15% of what? Of your original $1000? No, of your present balance, $1100. The effect is the same as compound interest.
There is the fundamental difference that interest is normally a fixed rate: you get such-and-such percent a year as spelled out in a contract. But change in the value of a stock depends on many factors, none of them guaranteed.