A mortgage that has a fixed interest rate for the first part of the mortgage (usually 3, 5, or 7 years), and an adjustable interest rate for the remainder of the mortgage.
A mortgage that combines some attributes of a fixed rate mortgage with attributes of an adjustable rate mortgage (e.g., a loan that is fixed for 5 years but then becomes an ARM).
A mortgage that combines some attributes of fixed rate mortgages with other attributes of adjustable rate mortgages. E.g. a loan which is fixed for 5 years but then reverts to an ARM.