I believe a golden cross is when a shorter term moving average crosses above a long-term moving average. So, the 50-MA crossing above the 200-MA would be a "golden cross. But the 50-MA crossing below the 200-MA is not.
Though a longer-term moving average carries more weight as a support (the 200), the shorter-term moving average shows the more recent trend. Technically, the 50 moving below the 200 would be considered a "death cross" if I understand correctly. See this link: