What is the definition of The Glass-Steagall Act?

The Glass-Steagall Act was a piece of legislation passed in the US in the 1930s which separated commercial banks and investment banks. The aim was to protect the customers of commercial banks from the riskier activities of investment banks.

The Glass-Steagall Act was repealed in the late 1990s by the Clinton administration and since then many banks have become large organizations participating in both investment banking and commercial banking (JPMorgan, Citi, Barclays etc.).