What is a ZCTA? It is similar to a ZIP code

ZCTA or ZCTA5 stands for ZIP Code Tabulation Area.

ZCTAs are the US Census Bureau's geographic rendering of ZIP Codes. ZIP codes are postal service identification codes but don't represent specific, consistent, geographic boundaries. ZCTAs are the Census Bureau's estimation of the geographic area of those ZIP codes. 

Whenever data are from the US Census Bureau, you can create maps and look at data by ZCTA. This is a good approximation of ZIP codes. 

Check out ZIP Code Tabulation Areas (ZCTAs) from the Census Bureau for more detailed information: https://www.census.gov/programs-surveys/geography/guidance/geo-areas/zctas.html