Deflation

Falling prices across an entire economy. Deflationary years were quite common under the gold standard when prices were stable over the long run, with some up and some down years. But deflation tends to be a problem in the modern era since it is often associated with falling nominal incomes. Since debt repayments are fixed in nominal terms, deflation often leads to a crisis as debtors struggle to repay their loans. Not to be confused with disinflation. For more, see this Explainer.