If a bond (= a document showing that money has been borrowed that will be paid back at a particular interest rate) is callable, the organization that lends the money can ask for it to be paid back before the end of a certain time.

The bonds were not callable, meaning the organization could not refinance when interest rates dropped.

Callable bonds can be redeemed before maturity at the issuer's discretion. 可赎回债券可在到期前由发行人自行决定赎回。