"What's a terminating decimal?"... A terminating decimal is a decimal that ends/has a finite number of digits. This is opposite to a repeating decimal, which never ends.
A terminating decimal is where decimals are written in infinite number of digits. Something written in like 9.183974829642364... or 10.916234753298... 67.8589612347....
Non-terminating decimals are decimals that end with 8.33333333... or 9.99999999999.... 16.66666666666...