Government debt ("public debt", "national debt") is money owed by government, at any level (central government, federal government, national government, municipal government, local government, regional government).
It's possible to consider this an indirect debt of the tax payers.
Government debt can be divided into internal debt, owed to lenders within the country, and external debt, owed to foreign lenders. It consists of government bonds, bank loans, and according to some measures, unfunded liabilities such as pension plan payments and goods and services the government has contracted for but not yet paid.