ringwall n.

a roughly circular ring of cliffs or mountains surrounding an area such as an impact crater or a lunar mare

Also fig.

Originally as a genuine term in geology; now largely confined to SF.


  • [1858 C. P. Smyth Astron. Exper. Peak of Teneriffe iii. v. 306

    It…gave us the erroneous idea of a double crater; an exterior ring-wall of brown, and an inside one of white, material.]

  • [1897 Science 29 Oct. 657/2

    Volcanic activity, as a cause of topographic features, has here been manifested…in explosive discharges, forming craters surrounded by circular ring-walls of débris.]

  • 1942 W. Ley Luna—Goddess of Love in Amazing Stories May 259/1 page image Willy Ley bibliography

    When the newly invented telescope was then directed at the moon and astronomers saw the ringwalls for the first time they felt convinced that these circular walls were artificial—nothing natural on Earth looked like them—visible signs of the activity of the Selenites that might, after all, be less lazy and more human than Kepler had imagined. They took the walls to be immense fortifications, built to protect cities.

  • 1944 W. Ley Moon Mysteries in Astounding Science-Fiction Dec. 115/2 page image Willy Ley bibliography

    The second and in certain respects most puzzling type are the numerous ringwalls or craters which range all the way from gigantic ‘walled plains’—of which Clavius is a fine example—to ‘normal’ Moon craters like Copernicus, and small ‘craterlets’ to tiny ‘beads’.

  • 1953 R. Z. Gallun Comet’s Burial in Science Fiction Stories (#1) 55 page image Raymond Z. Gallun bibliography

    A hell of silence, some of it beautiful: Huge ringwalls. Blazing sunlight, inky shadow. Grey plains, black sky.

  • 1967 B. Bova Fifteen Miles in Magazine of Fantasy & Science Fiction May 64/1 page image Ben Bova bibliography

    He stepped down from the jumper—a rocket motor with a railed platform and some equipment on it, nothing more—and planted his boots on the solid rock of the ringwall’s crest. With a twist of his shoulders to settle the weight of the pressure-suit’s bulky backpack, he shambled over to the packet of seismic instruments and florescent [sic] marker that the priest had left there.

  • 1993 P. Anderson Harvest of Stars (1994) 139 Poul Anderson bibliography

    The train climbed Tycho’s ringwall, swooped down again, whizzed across the crater floor, and plunged underground near Skyview Tower.

  • 2009 M. Stover Luke Skywalker & Shadows of Mindor xiii. 179 page image Matthew Stover bibliography

    This had an effect like a slow-motion fusion blast, as the powerful thermal updraft sucked huge quantities of dust up into the firestorm, where the dust ignited in turn, becoming an expanding ringwall of flame that swept across Mindor’s shattered landscape toward the battle that raged around the volcanic dome.

Research requirements

antedating 1942

Earliest cite

Willy Ley

Research History
Fred Galvin submitted a 1949 cite from "The Conquest of Space"; Mike Christie checked the 1944 first magazine appearance and discovered that the term was used in that version too.

Ben Ostrowsky submitted a 2009 cite from Matthew Stover, used figuratively.

Earliest cite in OED2: 1950; OED3 has updated this to our 1944 quote.

Last modified 2023-10-23 01:27:21
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.