Consumer Price Index - the primary measure of inflation used by central banks to set interest-rate policy.
CPI tracks the change in price of a basket of goods and services over time. Central banks target a CPI level (typically 2%) and adjust interest rates to steer inflation toward that target. Above-target CPI often triggers rate hikes, which typically strengthen the currency.
Monthly CPI releases are high-impact events for pairs involving the currency's country, particularly USD pairs when US CPI is published.