In this title the following words have the meanings indicated. “Appurtenance and environmental setting” includes: paved or unpaved walkways and driveways; trees; landscaping; pastures; croplands; waterways; and rocks. “Commission” includes a historic district commission or a historic preservation commission. “Demolition” includes any willful neglect in the maintenance and repair of a structure, other than the appurtenance and environmental setting of the structure, that: is not due to a financial inability to maintain and repair the structure; and threatens to result in a substantial deterioration of the exterior features of the structure. “District” means a significant concentration, linkage, or continuity of sites, structures, or objects united historically or aesthetically by plan or development. “Person” includes a unit of local government. “Routine maintenance” means work that: does not alter the exterior fabric or features of a site or structure; and has no material effect on the historical, archaeological, or architectural significance of the site or structure. “Site” means the location of: an event of historic significance; or a structure or ruin that possesses historic, archaeological, or cultural significance. “Structure” means a combination of material to form a construction that is stable. “Structure” includes: a building; a stadium; a reviewing stand; a platform; staging; an observation tower; a radio tower; a water tank or tower; a trestle; a bridge; a pier; paving; a bulkhead; a wharf; a shed; a coal bin; a shelter; a fence; a display sign that is visible or intended to be visible from a public way; and a part of a structure.