Definition of pycnostyle in US English:

pycnostyle

noun

Architecture
  • A building, especially one of classical or neoclassical design, having a row of columns placed close together, typically so that the distance between adjacent columns is equal to one and a half times the diameter of a column.

adjective

Architecture
  • Having or designating such an arrangement of columns.

Origin

Early 18th century; earliest use found in John Evelyn (1620–1706), diarist and writer. From French pycnostyle building having a distance between adjacent columns equal to one and a half times the diameter of a column or its etymon classical Latin pycnostȳlos (of a building) having a distance between adjacent columns equal to one and a half times the diameter of a column (Vitruvius) from ancient Greek πυκνο- + στῦλος column.

Pronunciation

pycnostyle

/ˈpɪknəʊstʌɪl/