What is maturity matching?

Answer 1

Matching the maturity of your assets with the timing (maturity) of your obligations. This can mean a pension fund buying a bunch of bonds that mature in the years when it is going to have to pay a bunch of benefits. ("bunch" being intentionally vague, but the same in both cases.)

It can also mean buying a certificate of deposit at a bank that matures in three years because you have a kid that is going to start college in three years.