Definition of pediplain in US English:

pediplain

noun

Geology
  • An extensive plain formed in a desert by the coalescence of neighboring pediments.

    • ‘Individual pediments can coalesce to form extensive surfaces called pediplains, commonly several thousand square kilometres in extent.’
    grassland, flatland, lowland, pasture, meadowland, open country, prairie, savannah, steppe
    View synonyms

Origin

1930s: from pediment + plain.

Pronunciation

pediplain

/ˈpedəˌplān/