price index vs price level

price index and price level both are nouns.

Word	Noun	Adjective	Verb	Adverb
price index	Yes	No	No	No
price level	Yes	No	No	No

As nouns, price index and price level are synonyms defined as:

price index and price level: an index that traces the relative changes in the price of an individual good (or a market basket of goods) over time

price index (noun)	price level (noun)
an index that traces the relative changes in the price of an individual good (or a market basket of goods) over time	an index that traces the relative changes in the price of an individual good (or a market basket of goods) over time