This guide is intended to help clarify commonly used terms and phrases in the field of historic preservation. It also includes definitions of organizations that are often involved in historic preservation work.
Key Words & Phrases
Adaptive Use: Utilization of a building, structure, or site other than for its historic purpose, normally entailing some modification of the resource.
Adverse Effect: Circumstance in which a project may alter characteristics that qualify a specific property in a manner that will diminish the integrity of that property.
Advisory Council of Historic Preservation (ACHP): An independent federal agency that promotes the preservation, enhancement, and sustainable use of the nation’s diverse historic resources and advises the President and Congress on national historic preservation policy.
Archaeology: The study of past peoples through their material remains.
Certificate of Appropriateness (COA): Written approval of a permit application for work in a local historic district by the Historic District Commission, indicating that the work is appropriate and does not adversely affect a resource.
Certified Local Government (CLG): A county, township or municipality that has been endorsed by the SHPO and NPS to participate in the national preservation program while maintaining standards consistent with the NHPA and SOI Standards for Archaeology and Historic Preservation.
Character-defining Features: Prominent or distinctive aspects, qualities, or characteristics of a historic property that contribute significantly to its physical structure or appearance.
Contributing Resource: A building, structure, object, or site adding to the significance of a historic district.
Cultural Landscape: A geographic area, including both cultural and natural resources and the wildlife or domestic animals therein, associated with a historic event, activity, or person or exhibiting other cultural or aesthetic values.
Demolition: Demolition is the act of dismantling, razing, or destroying a building or structure, using methods like wrecking balls, machinery, or explosives.
Demolition by Neglecting: Neglecting to maintain, repair, or secure a resource resulting in the deterioration of exterior features and/or loss of structural integrity of the resource.
Design Guidelines: Standards of appropriate activity to preserve the historic and architectural character of a building, structure, object, or site.
Eligible: Meets the criteria for listing in a historic register but is not officially listed.
Federal Rehabilitation Tax Credit: A 20% income tax credit for the rehabilitation of historic, income-producing buildings listed in or eligible to be listed in the National Register of Historic Places.
Geographical Information System (GIS): A computer system for capturing, storing, checking, and displaying data related to positions on Earth’s surface.
Heritage Tourism: A form of travel focused on experiencing and learning about the history, culture, and traditions of a place. It often includes visiting historic sites, museums, cultural landmarks, and communities to better understand how the past has shaped the present.
Historic American Building Survey (HABS)/Historic American Engineering Record (HAER)/Historic American Landscape Survey (HALS): National Park Services (NPS) programs that document significant architecture, engineering resources, and landscapes through measured drawings, photographs, and written histories housed at the Library of Congress.
Historic Context: An organizing structure for interpreting history that groups information about historic properties that share a common theme, geographical location, and time period.
Historic District: A significant concentration, linkage, or continuity of sites, buildings, structures, or objects united historically or aesthetically by plan or physical development.
Historic Preservation: The process of identifying, protecting, enhancing, and interpreting buildings, structures, sites, objects, districts, and landscapes of historic and cultural significance.
Historic Preservation Easement, Covenant or Agreement: A legal contractual document, either mandatory or voluntary, which protects a significant historic property, either perpetually or for a designated period of time.
Historic Resource: Any historic building, structure, object, or site included in or eligible for the National Register of Historic Places.
Historic Significance: The meaning or value ascribed to a building, structure, object, site, or district based on criteria for evaluation for an established designation program.
Historic Structure Report: A report providing documentary, graphic, and physical information about a property’s history and existing condition and outlining appropriate treatment and scope of work for repair, changes, and ongoing maintenance.
Integrity: The ability of a property to convey its significance through its physical features or characteristics.
Inventory: Catalog of buildings, structures, objects, and sites within a specified area including those listed, eligible for listing, or non-eligible for listing in the National Register of Historic Places.
Mitigation: An action to minimize or offset an adverse effect to a historic property.
Memorandum of Agreement (MOA): A formal document used to outline an agreement between separate entities, groups, or individuals.
Mothball: Temporary measures to protect a building from weather and vandalism.
National Historic Landmark (NHL): A district, building, structure, site, or object of national significance, designated by the U.S. Secretary of the Interior for possessing exceptional value or quality in illustrating or interpreting the heritage of the United States.
National Historic Preservation Act (NHPA): A federal law that fosters the identification, evaluation, and protection of historic and prehistoric resources in the United States enacted in 1966.
National Main Street Center (Main Street America): A subsidiary of the National Trust for Historic Preservation (NTHP) that directs a nationwide network to encourage preservation-based community revitalization.
National Park Service (NPS): A federal agency within the Department of the Interior that works to preserve unimpaired the natural and cultural resources and values of the National Park System for the enjoyment, education, and inspiration of this and future generations. The agency oversees multiple programs provided through the National Historic Preservation Act.
National Register of Historic Places (NRHP): The Official list of the nation’s historic places worthy of preservation.
National Trust for Historic Preservation (NTHP): National non-profit membership organization that “protects significant places representing the nation’s diverse cultural heritage.
Non-Contributing Resource: A building, structure, object, or site that does not add to the significance of a historic district.
Period of Significance: Span of time in which a property attained the importance for which it meets the criteria for historic designation.
Preservation Plan: Document that details goals, priorities, and strategies for identification, evaluation, registration, and protection of historic properties and for promotion of and education on historic preservation.
Reconstruction: The act or process of depicting, by means of new construction, the form, features, and detailing of a non-surviving site, landscape, building, structure, or object for the purpose of replicating its appearance at a specific period of time and in its historic location.
Rehabilitation: The act or process of making possible a compatible use for a property through repair, alterations, and additions while preserving those portions or features which convey its historical, cultural, or architectural values.
Restoration: The act or process of accurately depicting the form, features, and character of a property as it appeared at a particular period of time by means of the removal of features from other periods in its history and reconstruction of missing features from the restoration period.
Secretary of the Interior’s Standards: Typically refers to the Standards for Treatment of Historic Properties, Preservation, Rehabilitation, Restoration, & Reconstruction. However, Standards are also available for Preservation Planning, Identification, Evaluation, Registration, Qualification, and Historical, Archaeological, Architectural, and Engineering Documentation.
Section 106 (of the NHPA): The process required of federal agencies to consider the effects of projects they carry out, permit, or fund on historic properties (54 U.S.C. 306108).
State Historic Preservation Offices (SHPO): Established by the NHPA, the agency in each state or territory that administers the national historic preservation program. The Officer is appointed by the Governor to oversee its functions.
Architectural Styles
Late Nineteenth-Century Styles
Queen Anne: The Queen Anne style is a highly decorative and eclectic form that was popular in the United States during the late 19th century, roughly from the 1880s to early 1900s. It is known for its asymmetrical façades, steeply pitched roofs, ornate detailing, and varied wall textures such as patterned shingles, brick, or wood. Common features include prominent front-facing gables, wraparound porches, bay windows, and decorative trim known as “gingerbread” ornamentation. Towers or turrets are also often present, adding to the style’s picturesque and visually complex appearance. Queen Anne homes were designed to showcase craftsmanship and individuality, making each structure unique.
Queen Anne Cottage: The Queen Anne Cottage style is a smaller, simplified variation of the more elaborate Queen Anne architectural style that was popular in the late 19th century. While it retains some of the signature features of Queen Anne design—such as asymmetry, decorative trim, and varied rooflines—it is more modest in scale and ornamentation. These homes often feature a steeply pitched roof, a front-facing gable, and a welcoming porch, but with less elaborate detailing than larger Queen Anne houses.
Gothic Revival: The Gothic Revival architectural style gained popularity in the United States during the mid-19th century, inspired by medieval European Gothic architecture. It is characterized by steeply pitched roofs, pointed arch windows and doorways, decorative tracery, and ornate detailing such as finials and vergeboards. Many buildings in this style also feature vertical emphasis, creating a sense of height and grandeur. Gothic Revival was commonly used for churches, colleges, and some residential homes, reflecting romantic ideals and a fascination with the past.
Italianate: The Italianate architectural style was popular in the United States from the mid-19th century, inspired by the rural villas of Italy. It is recognized by its low-pitched or flat roofs, widely overhanging eaves with decorative brackets, and tall, narrow windows often crowned with arched or curved window hoods. Many Italianate buildings also feature cupolas or towers, adding to their vertical emphasis and picturesque appearance. Common in both urban and rural settings, the style was used for homes, commercial buildings, and public structures.
Vernacular: Vernacular architecture refers to buildings designed based on local needs, available materials, and regional traditions rather than formal architectural styles. It is shaped by the environment, climate, and cultural practices of a specific place, resulting in highly practical and often modest structures. Common examples include simple farmhouses, log cabins, and regional housing forms that evolved over time through everyday use and craftsmanship. Because it is rooted in local building knowledge rather than formal design movements, vernacular architecture varies widely from one region to another and reflects the practical ingenuity of the people who built it.
Early Twentieth-Century Styles
Craftsman: The Craftsman architectural style emerged in the early 20th century as part of the broader Arts and Crafts movement, emphasizing handcrafted quality, natural materials, and simplicity of design. Homes in this style typically feature low-pitched gabled roofs, wide overhanging eaves with exposed rafters, and inviting front porches supported by tapered or square columns. Interiors often highlight built-in cabinetry, woodwork, and open floor plans that prioritize function and craftsmanship over ornamentation.
American Four Square: The American Foursquare is an architectural style that is known for its simple, boxy form, typically two-and-a-half stories tall with a square floor plan that efficiently divides interior space into four rooms on each floor. Most Foursquare homes feature a low-hipped roof with a central dormer and a wide front porch supported by columns.
Tudor Revival: The Tudor Revival architectural style mimicking 16th-century English medieval, rustic, and early Renaissance homes. Key features include steeply pitched roofs, prominent cross-gables, decorative half-timbering, tall, narrow windows with diamond-paned casements, and massive brick or stone chimneys. Exterior walls commonly combine brick, stone, and stucco to create a picturesque, storybook appearance.
Colonial Revival: The Colonial Revival architectural style became widely popular in the United States in the late 19th and early 20th centuries, inspired by early American colonial architecture from the 17th and 18th centuries. It is characterized by its symmetrical facades, evenly spaced windows, and centered front doors often accented with decorative pediments, columns, or fanlights. Roofs are typically side-gabled, and materials commonly include brick or wood siding.
Neoclassical: The Neoclassical architectural style became popular in the United States in the late 19th and early 20th centuries, drawing inspiration from the classical architecture of ancient Greece and Rome. It is characterized by its grand scale, symmetrical form, and prominent use of columns, often of the Doric, Ionic, or Corinthian orders. Buildings in this style frequently feature full-height porches, triangular pediments, and elaborate entrances.
Dutch Colonial Revival: The Dutch Colonial Revival architectural style gained popularity in the United States in the late 19th and early 20th centuries, inspired by early Dutch settler homes of the 17th and 18th centuries. Its most distinctive feature is the gambrel roof with flared eaves, often extending over a full-width or partial front porch. These homes are typically symmetrical, with centered entryways and evenly spaced windows, and are commonly constructed of wood or brick.
Mid-Twentieth Century Styles
Minimal Traditional: The Minimal Traditional architectural style emerged in the United States during the 1930s and remained popular through the post-World War II housing boom. These homes are typically small to medium in size, with low or moderate-pitched roofs, minimal eave overhangs, and simple, compact floor plans designed for efficiency and affordability. Exterior details are restrained, though they may include subtle references like modest shutters or a small front porch.
Mid-century Modern: Mid-century modern architecture is a post-World War II design style (roughly 1945-1970) characterized by clean lines, flat planes, large windows, and an integration with nature, often focusing on functionality over ornamentation. Influenced by Bauhaus and the International Style, it features open floor plans, exposed materials like steel and wood.
Ranch: The Ranch architectural style became widely popular in the United States during the mid-20th century, especially from the 1940s through the 1970s. It is characterized by its long, low profile, single-story layout, and open floor plans that emphasize informal, modern living. Ranch homes often feature large picture windows, attached garages, and sliding glass doors that connect indoor spaces to patios or backyards. Influenced by modernist ideas and the casual lifestyle of postwar America, the Ranch style prioritized simplicity, functionality, and ease of movement within the home.
Split-entry: The split-entry architectural style, became especially popular in the United States during the mid-20th century, particularly in suburban developments from the 1950s through the 1970s. It is defined by a front entry that opens to a small landing, where a short set of stairs leads both up to the main living spaces and down to a lower level. Split-entry homes were valued for their practical use of space and affordability, making them a common choice in expanding suburban neighborhoods.