helicline

Blend of helico- +‎ incline^[1] or combination of heli- +‎ -cline, from Ancient Greek ἕλιξ (hélix, “spiral”).^[2] Attested from the 1930s (see quotations below).

• IPA^(key): /ˈhɛlɪˌklaɪn/

helicline (plural heliclines)

1. (now uncommon, architecture) A curving or spiral-shaped ramp; (especially) the ramp at the 1939 New York World's Fair Theme Center.
   • 1937 March 25, “Fair Designers Make Theme Building Plans”, in The Iron Age, page 62:

     A bridge will link the sphere to the tower, while from the latter a ramp 900 ft. long will slope gently to the ground curving around the fountain basis beneath the sphere in a huge three-quarter circle. This ramp is described as the “helicline,” and will be 50 ft. high at the top

   • 1939 May 11, “Notes & Topics”, in The Architects' Journal, page 758:

     We have heard rumours of several good buildings at the Fair, but the newscuttings have not so far found time to tell us about them among attractions so sensational that no previously known words would cover them. “Democracity” is studded with Trylons and Perispheres, slides on Heliclines and sploshes in Aquacades.

   • 1940 November 4, “Taps for the Fair”, in Newsweek, page 19:

     Stepping to the helicline of the flood-lighted Perisphere at the New York World's Fair at midnight Sunday, an Army bugler sounded taps, signalizing the beginning of an epic grand finale.

   • 1999, “Max Abromovitz”, in Encyclopedia of World Biography Supplement, volume 18, page 1:

     The Perisphere housed the exhibit, where visitors entered by means of “the world’s longest escalator,” and exited down a 950-foot ramp, called the Helicline.

   • [2011, Francis D.K. Ching, A Visual Dictionary Of Architecture, page 239:

     stepped ramp ¶ A series of ramps connected by steps.¶ helicline ¶ A curved ramp.]