1911 Encyclopædia Britannica/Extrados
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EXTRADOS (extra, outside, Fr. dos, back), the architectural term for the outer boundary of the voussoirs of an arch (q.v.).
See also Voussoir on Wikipedia; and our 1911 Encyclopædia Britannica disclaimer.
EXTRADOS (extra, outside, Fr. dos, back), the architectural term for the outer boundary of the voussoirs of an arch (q.v.).