Interest Rate Ceiling

What Does Interest Rate Ceiling Mean?
The maximum interest rate that a financial institution can charge a borrower for an adjustable rate mortgage or loan according to the contractual terms of the mortgage or loan. This interest rate is expressed as an absolute percentage. 

Investopedia explains Interest Rate Ceiling
For example, the terms of the loan might state that the interest rate can never exceed 19%. 
An interest rate ceiling is sometimes used interchangeably with the term "lifetime interest rate cap". However, an interest rate cap is usually expressed as a maximum change allowed in an initial interest rate.

For example, a 5% interest rate cap would suggest that the interest rate on the borrower's loan can fluctuate within a 5% range during any specific rate adjustment period.