Definition of plein-airism in US English:

plein-airism

(also plein-airisme, plein air-ism)

noun

Art
  • The theories, practices, or style of the plein-air school of painting.

Origin

Late 19th century; earliest use found in The Century Illustrated Monthly Magazine. From plein-air + -ism.

Pronunciation

plein-airism

/pleɪnˈɛːrɪz(ə)m/