Definition

1. Noun:
   • An architectural element: A spandrel is the approximately triangular space or surface area between two adjacent arches, or between an arch and a rectangular enclosure (like a lintel or cornice) above it.
   • A structural byproduct: In broader evolutionary biology, the term is used metaphorically to describe a phenotypic characteristic that is a secondary byproduct of the evolution of some other trait, rather than a direct product of adaptive selection.

Usage Examples

• Noun (Architecture):
  • The cathedral's spandrels are decorated with intricate mosaics.
  • The architect designed simple, unadorned spandrels to emphasize the arches' clean lines.
• Noun (Biology/Evolution):
  • The evolutionary biologist argued that the color was merely a spandrel, not an adaptation for camouflage.

Advanced Usage

• "Spandrel" in evolutionary theory: This metaphorical use, popularized by Stephen Jay Gould and Richard Lewontin, refers to a trait that exists not because it was directly selected for, but because it is a necessary architectural consequence or byproduct of other selected traits. The original architectural term is used as an analogy.
  • Their paper challenged the adaptationist program by highlighting the importance of evolutionary spandrels.

Variants and Related Words

• Spandril: An alternate, less common spelling of "spandrel."
• Spandrel wall: A wall built in the spandrel space, often found in bridge construction.
• Spandrel glass: A type of opaque glass used to cover the spandrel areas in curtain wall buildings.

Synonyms

• Architectural Synonyms: Pendentive (though technically different, a pendentive is a spherical triangle supporting a dome), tympanum (a similar semi-circular or triangular decorative wall surface, often over a door).
• Biological Metaphor Synonyms: Byproduct, epiphenomenon, non-adaptive trait.

Related Phrases

• Spandrel beam: In structural engineering, a beam that runs along the exterior of a building from column to column, often located at the floor levels, which helps form the spandrel area.
  • The spandrel beam also supports the exterior wall panels.

Related Idioms

• No direct idioms exist for "spandrel." The term is highly specialized in architecture and its metaphorical extension in biology.

Noun

1. an approximately triangular surface area between two adjacent arches and the horizontal plane above them