"Low volatility" refers to a situation where the value or price of something doesn't change very much or rapidly over time. It means that there is less risk or uncertainty involved as the movements are steady and predictable. Full definition
One important point they make is that the low vol anomaly is more than the idea that stocks with low volatility outperform stocks with high volatility. (abnormalreturns.com)
A dollar invested in 1968 in the top 20 % of lowest volatility stocks in a portfolio would be worth just over $ 100 in 2015. (realsmartbeta.com)
A significant body of research confirms the efficacy of investing in low volatility stocks over high volatility stocks. (valuewalk.com)