What does maturity mean?
A long-term investment, a bond, for example, reaches maturity when it pays out the original purchase amount to the investor and interest earned on the investment naturally ends. Investments that reach maturity are usually lending-type financial instruments where the investor essentially lends money to the bond issuer. If an investment has reached maturity it means that the investment agreement has come to an end.
Maturity is also used in more general terms to describe any investment that reaches its conclusion and pays out a sum of money.