Definition of Portlandian in US English:

Portlandian

adjective

Geology
  • Of, relating to, or designating the uppermost division of the Jurassic of Europe, in which Portland oolite occurs, sometimes regarded as a stage lying above the Kimmeridgian.

noun

Geology
  • The Portlandian stage or series of rocks. Chiefly with the.

Origin

Mid 19th century; earliest use found in The North British Review. From the name of Portland + -ian, after Portland oolite.

Pronunciation

Portlandian

/pɔːtˈlandɪən/