arch
AHRCH
/ɑːtʃ/
A curved symmetrical structure spanning an opening and typically supporting the weight of a bridge, roof, or wall above it.
Relies on compression forces redirecting downward weight sideways into supports.
The story behind the word. Derived from Latin 'arcus', which originally referred to a archer's weapon or the curved rainbow across the sky. Roman engineers adopted the shape because wedge-shaped stones (voussoirs) pressed tightly together under gravity, converting vertical weight into stable lateral force.
Word relationships
- vault: An arch is a single two-dimensional structural span, whereas a vault is an extended three-dimensional arch forming a ceiling or roof.
Commonly confused with
- lintel: A lintel is a horizontal straight beam across an opening, while an arch uses a curved structure.
Word family
- arched (adjective): Constructed or formed as a curve.
- archway (noun): A passage under an arch.
Collocations
- gothic arch
- roman arch
- triumphal arch
- arch bridge
Idioms & expressions
- overarching theme
Example sentences
- "The stone arch spanned the river gracefully, carrying traffic safely across the canyon." Bridge Construction
- "Roman builders perfected the semi-circular arch, allowing them to construct immense aqueducts." Classical History
Memory hook
Think of an archer's curved bow—an arch spans across with that same distinct bend. Arch = Curved span.
When not to use
Do not confuse with a flat lintel or straight beam bridge.
Fun facts
- Until the Roman invention of concrete and perfected arch technology, buildings were severely limited by how far flat wooden or stone beams could stretch without snapping.
Explore more words
abutment, truss, load-bearing, viaduct, cantilever, deflection
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