FUNCTIONAL OBSOLESCENCE: is a reduction in the usefulness or desirability of an object because of an outdated design feature, usually one that cannot be easily changed. The term is commonly used in real estate, but has a wide application.
IN OTHER WORDS: Features of a home that are not practical or desirable that typically affect the price negatively.
EXAMPLES OF HOW IT RELATES TO REAL ESTATE:
Walking through one bedroom to get to another;
Front stairs that are taxing for buyers to have to walk up to get into the house;
A two level home with only one bathroom… on the first floor