PITI is an acronym for principal, interest, taxes, and insurance. These are the four primary components of a monthly mortgage payment. Here's how each of these four categories affects your payment. MORE: Read our guide for first-time home buyers. PITI meaning fully explained When buying a home, there are plenty of acronyms to unravel, including APR, PMI, DTI — and PITI. Let's break down PITI: Principal The mortgage principal is the remaining balance of the amount you borrowed to buy a home. For exam ...