A detailed explanation from my research
CPI most commonly means Consumer Price Index.
It measures how the prices of everyday goods and services—such as food, housing, transportation, and healthcare—change over time.
CPI is commonly used to measure inflation:
CPI rises → prices are generally increasing → inflation.
CPI falls → prices are generally decreasing → deflation.
For example, if CPI increases by 3% over a year, it roughly means that a typical basket of goods and services costs 3% more than it did a year earlier.