By free they mean able to make decisions for oneself as opposed to having the government make decisions for one, especially economic decisions.
By equality they mean equality in income, education, political and corporate power.
Women Prosper when Markets Are Free
They go into detail in the video...International Women's Day was founded by the American Socialist Party in 1909 and usually ends up celebrating women in government, politics, and statism, but let's look at something else. Cross-referencing data from the Fraser Institute, which looks at general economic freedom, and World Bank in the United Nations, which looks at gender disparity, we see that countries that are more economically free also have more gender equality.
But could this simply be due to "rich country effect," the idea that a wealthy country merely has more money to pay its women workers? Of course, there are particular examples to support both theories, but on average, globally, it's true that more economic freedom means more gender equality.