A spandrel is a space or surface created by the shape of an architectural structure. In buildings, it often means the roughly triangular area between an arch, a frame, or a curved roof and the surrounding structure.
The word also has a special meaning in evolutionary biology, where a spandrel is a trait that appears as a byproduct of another adaptation rather than because it was directly selected.
So, the meaning depends on context. In simple terms, a spandrel can be an unused architectural space or a biological feature that develops as a side effect. This guide explains both meanings with clear examples.
What Is the Basic Spandrel Definition?
The basic spandrel definition refers to a space or area that is formed by the shape of other structural parts. The word is most common in architecture, but it also appears in biology, especially in discussions about evolution.
In architecture, a spandrel may be the space between an arch and a surrounding rectangular frame. It can also describe the area between the top of a window and the floor above it.
The shape is often not a simple rectangle. It may be triangular, curved, or irregular because it follows the form of the structure around it.
For example, imagine a row of tall arches. Above each arch, there may be a small area that does not fit neatly into the main shape of the wall. That area is a spandrel.
In biology, the meaning changes. A biological spandrel is a feature that exists because of another trait or structural limitation. It may not have been directly created by natural selection for its present role.
So, the word has two major meanings:
- Architecture: a space or surface created between structural forms.
- Evolutionary biology: a trait that arises as a byproduct of another feature or process.
Spandrel in Architecture
The architectural meaning is the older and more common use of spandrel.
A spandrel is usually an area that fills the space between structural elements. It may be found near arches, windows, floors, roofs, or frames.
One common example is the area between an arch and a rectangular frame. Because the arch curves upward while the frame stays straight, empty areas appear on either side of the arch’s upper curve.
These areas can be plain or highly decorated. In historic buildings, architects often used spandrels as places for carvings, paintings, patterns, or other decorative details.
A spandrel does not always mean an empty space. It can be a real part of the wall or structure. The term describes its position and shape, not whether it has a practical function.
This makes the word useful when describing complex buildings.
Where Can You Find a Spandrel?
Spandrels can appear in many types of structures. They are especially easy to see in buildings with arches, large windows, or repeated structural patterns.
Common locations include:
| Location | What the spandrel refers to |
|---|---|
| Above an arch | The area between the arch and the surrounding frame |
| Between windows | A structural or decorative area separating window openings |
| Between floors | The area around the edge of a building between floor levels |
| Under a roof | A space shaped by the roof and supporting structure |
| Between curved forms | An area left by intersecting or surrounding curves |
| In bridges | A region between an arch and the deck or roadway |
In modern buildings, the term may also describe a spandrel panel. This is often a panel located between windows or between a window and the floor slab.
These panels can help hide structural elements, insulation, or building services while keeping the outside of the building visually smooth.
What Is a Spandrel Panel?
A spandrel panel is a building panel used in the area between windows or other parts of a building’s exterior.
In glass buildings, the word is especially important. A building may have large windows on each floor, but not every part of the exterior can be transparent. The area between the window sections may contain a spandrel panel.
A spandrel panel can cover parts of the building that are not intended to be visible from outside. For example, it may conceal:
- Floor edges
- Insulation
- Structural elements
- Mechanical systems
- Interior walls
- Ceiling spaces
These panels can be made from glass, metal, stone, or other materials.
A spandrel glass panel, for example, may look similar to a window from outside. However, it is usually designed to hide the structure behind it rather than provide a clear view.
This distinction is important in modern architectural design.
Spandrel Examples in Architecture
Understanding a word becomes easier when you can picture it.
Example 1: An arched doorway
Imagine a rectangular wall with a large rounded doorway. The space between the top of the rounded arch and the straight top edge of the wall forms a spandrel area.
Example 2: A historic cathedral
A cathedral may contain large arches decorated with stone patterns. The areas around the upper parts of those arches can be spandrels.
Example 3: A modern office building
A glass office may have windows stretching across several floors. Between the windows, darker panels cover the edges of floors and other structural parts. These can be called spandrel panels.
Example 4: An arched bridge
A bridge with a large arch can contain spaces between the arch and the roadway above it. These areas may also be described using the term spandrel.
These examples show why the word is mainly about space, position, and structure.
Why Are Spandrels Important in Architecture?
Spandrels are important because they can serve both structural and visual purposes.
From a design point of view, a spandrel can turn an awkward space into a useful part of a building. Instead of leaving the area plain, an architect can decorate it or use it to conceal structural features.
In older buildings, spandrels were often used for artistic work. Stone carvings, painted scenes, and geometric patterns could make them important parts of the overall design.
In modern buildings, spandrel areas can have more practical roles. They may help cover insulation, floor edges, wiring, pipes, or other building components.
A good architectural design often makes such areas look intentional rather than accidental.
This is why a spandrel can be both functional and decorative.
Spandrel in Evolutionary Biology
The word spandrel has another important meaning in evolutionary biology.
In this context, a spandrel is a feature that develops as a byproduct of another evolutionary feature. The idea is used to question the assumption that every biological trait must have evolved because it directly provided an advantage.
The term became well known in evolutionary discussions through a famous paper by Stephen Jay Gould and Richard C. Lewontin.
Their argument used the architectural spandrel as a metaphor. In a building, a spandrel may exist because arches and other structural forms create it. The architect does not need to design the space as an independent feature.
In the same way, a biological feature might appear because of the way another trait is built or inherited.
This does not mean that every such feature has no value. A feature may later gain a useful role even if that was not the reason it first appeared.
The biological meaning is therefore more about origin than usefulness.
What Does Spandrel Mean in Evolution?
In evolution, the term is closely linked to the idea of exaptation and byproducts, although the concepts are not identical.
An adaptation is a trait shaped by natural selection because it helped organisms survive or reproduce.
A spandrel, in the Gould and Lewontin sense, may arise without being directly selected for its current form or role. It can result from constraints, developmental processes, or another adaptation.
A simple way to understand the difference is:
Adaptation: A trait develops because it provides a selected advantage.
Spandrel: A trait appears as a consequence of something else.
For example, if a physical structure creates a secondary feature automatically, that secondary feature may be compared to an architectural spandrel.
This idea encourages scientists to ask a useful question: Did this trait evolve for its present purpose, or did its present use come later?
That question can lead to a deeper understanding of evolution.
Architecture vs. Evolution: Spandrel Compared
The two meanings of spandrel may seem unrelated, but they share the same basic idea.
In both cases, something is created by the relationship between other parts.
| Feature | Architecture | Evolutionary biology |
|---|---|---|
| Basic meaning | A space formed by structural elements | A feature formed as a byproduct |
| Main context | Buildings and structures | Evolution and biology |
| Key idea | Shape creates the space | Another process creates the trait |
| Example | Area between an arch and frame | A trait arising from developmental constraints |
| Main question | Where is the space formed? | Why did the feature arise? |
The architectural meaning provides the image behind the biological metaphor.
Think of an arch. Once the arch and surrounding frame exist, a certain space may appear naturally between them. The space does not need to have been the main reason for building the arch.
Evolutionary spandrels work as a similar concept.
How to Use Spandrel in a Sentence
The word spandrel is mainly used in technical writing, architecture, art history, and evolutionary biology.
Here are some clear examples:
- “The architect decorated the spandrels above the arches with floral designs.”
- “The building uses glass spandrel panels between each row of windows.”
- “The researchers discussed whether the trait was an adaptation or a biological spandrel.”
- “The carved spandrel added detail to the entrance.”
- “The architect used the spandrel space for a geometric pattern.”
When writing for a general audience, it helps to explain the word the first time it appears.
For example:
“The church has ornate spandrels, the spaces between its arches and surrounding walls.”
This gives readers the meaning without requiring specialist knowledge.
Common Confusion About the Word Spandrel
The word can be confusing because it has a specialized meaning in more than one field.
One common mistake is to assume that a spandrel always means an empty space. In architecture, it can refer to a filled structural or decorative area as well.
Another mistake is to assume that a biological spandrel is simply a useless trait. That is too simple. The concept is about how a feature originated, not just whether it has a current function.
A feature that began as a byproduct can later become useful. Its present value does not necessarily tell us why it first appeared.
It is also useful to distinguish spandrel from nearby architectural terms such as arch, panel, and wall.
An arch is a curved structural form. A spandrel is an area created around such forms.
Understanding that relationship makes the definition much easier to remember.
People Also Ask About Spandrel Definition
What is the simple definition of spandrel?
A spandrel is an area or surface formed by the shape of surrounding architectural parts. In biology, it can mean a trait that arises as a byproduct of another feature or process.
What is a spandrel in architecture?
In architecture, a spandrel is usually the area between an arch and its surrounding frame, or a similar area between structural elements. It may be decorative, structural, or both.
What is a spandrel panel?
A spandrel panel is a panel placed between windows or other parts of a building. It can hide structural elements, insulation, floor edges, or building systems.
What is a spandrel in biology?
In evolutionary biology, a spandrel is a feature that arises as a byproduct of another trait, developmental process, or structural constraint rather than being directly selected for its present role.
Is a spandrel an empty space?
Not always. A spandrel can be an open-looking space, but it can also be a solid wall area, decorative surface, or panel. The term mainly describes its position and relationship to other structures.
What is the difference between a spandrel and an arch?
An arch is the curved structural element itself. A spandrel is the area formed around or between an arch and other structural elements.
Why is the term spandrel used in evolution?
The term is used because an architectural spandrel can be created as a consequence of other structures. In evolution, the metaphor describes traits that may arise as byproducts rather than direct adaptations.
Conclusion
The spandrel definition changes slightly depending on the field. In architecture, it describes a space, surface, or panel formed by surrounding structural elements, often near arches, windows, or floors.
In evolutionary biology, it describes a feature that may arise as a byproduct of another process or adaptation. The shared idea is simple: something exists because of the way other parts come together.
Once you understand this core idea, the word becomes much easier to recognize in architectural descriptions, biology discussions, and academic writing.
I am David Cooper, an English language enthusiast and content creator at Metaphounivers, dedicated to simplifying grammar and vocabulary for learners worldwide. I help students build confidence and improve their communication skills through clear, practical lessons.
