All of the above are correct

It is the amortization of the principal of the loan.

An amortization chart is created from an amortization table or amortization schedule to show visually how the balance, cumulative interest, and principal change over the time.

Breakdown of the amortization in to Interest and Principal is called Amortization schedule. This is useful customers to know how much interest is stuffed in to an amortization. These days EMI is most popular way of amortization, where customer pays same amount throughout amortization period. With Amortization Schedule customer can know how much interest he is paying in every amortization. Find more info at www.investorwords.com/202/amortization_schedule.html

Debit amortization expenses
Credit intangible assets