Which option does NOT define "improvement" in real estate?

In real estate terminology, "improvement" typically refers to any addition made to the land that enhances its value or utility. This includes physical structures or enhancements that contribute to the property's overall usefulness or aesthetic appeal. Options like streets, sanitary sewer systems, and foundations are all integral parts of a property’s infrastructure or structural integrity, thereby qualifying as improvements.

Trade fixtures, however, are items that a commercial tenant installs in a leased space to facilitate their business operations. While they may be fixtures in terms of physical attachment to the property, they are essentially personal property of the tenant and can typically be removed upon lease termination. Therefore, trade fixtures do not fulfill the definition of an improvement in real estate, as they do not add intrinsic value to the property itself in the same way that streets, sewer systems, or foundations do.