What is ROE means

It's Return on Equity. Net Income divided by Stockholder's Equity. It's basically what the net profits of the company as a percent of the total equity. It's like you investing in something, getting something back out of it, and what the return is you got out of it as a percent.

Everything you ever wanted to know about ratios and probably stuff you didn't want to know:
Investopedia.com: Financial Ratio Tutorial