Definition of prograde in English:

prograde

adjective

  • 1Astronomy
    (of planetary motion) proceeding from west to east; direct.

    The opposite of retrograde
    • ‘The fact that the moons move in a circular prograde orbit, close to the asteroid's equatorial plane, also lends support to this scenario.’
    • ‘Two of the new moons have prograde orbits - that is, they orbit in the same direction as the planet turns.’
    • ‘While this relatively simple model will explain prograde and retrograde motion qualitatively, it fails on detail, so additional complications were added to improve the fit to reality.’
    • ‘Numerous small, distant satellites in both prograde and retrograde orbits have been discovered recently.’
    • ‘These are all in circular prograde orbits near Neptune's equatorial plane, and they probably formed in place.’
  • 2Geology
    (of a metamorphic change) resulting from an increase in temperature or pressure.

    • ‘These rocks display clear prograde metamorphism that peaks in granulite facies.’
    • ‘Given the stability of zircon during metamorphic processes, it may be assumed that the formation of new zircons in prograde metamorphism is not significant until the appearance of melt.’
    • ‘Both thrust and normal faults initiated synchronously with Miocene prograde metamorphism and melting, and have moved episodically since then.’
    • ‘The apparent critical temperature between 560 to 600°C for monazite growth at Ballachulish is broadly consistent with several previous studies of monazite in prograde metamorphic sequences.’
    • ‘During the cooling stage the isotherms will retreat towards the host rock-container interface, leaving behind a sequence of largely prograde metamorphic zones outside the sarcophagus of melted and recrystallized granite.’

verb

[NO OBJECT]Geology
  • (of a coastline) advance towards the sea as a result of the accumulation of waterborne sediment:

    ‘these oolites were probably deposited as part of the coastal sand-barrier complex as it prograded basinwards’
    • ‘The zone of active deltaic growth faulting (and margin-parallel maximum horizontal stress) has shifted basin-wards as the delta system has rapidly prograded across the shelf.’
    • ‘As the facies progrades, it incorporates gray, fine-grained, thin sandstone beds with sharply defined lower boundaries, wave-rippled lamination, and rippled tops.’
    • ‘Through time, the basin shrank as it filled with sediment that prograded inward along the margins, most rapidly along the Eastern Shelf.’
    • ‘In time, as the Ecca Sea filled with sediment and the deltas prograded basinward, large tracts of river channels and floodplains emerged.’
    • ‘A slightly later phase of deglaciation occurred when the ice margin retreated north into St. George's Channel, forming the raised ice contact delta at the Screen Hills, which prograded southwards into high relative sea level.’

Origin

Early 20th century (as a verb): from pro- ‘forwards’+ retrograde.

Pronunciation:

prograde

/ˈprəʊɡreɪd/