umbilicus

Etymology

Borrowed from Latin umbilīcus (“navel”).

noun

1. (anatomy) navel
2. (botany) hilum
3. (zoology) A depression or opening in the center of the base of many spiral shells.
4. (zoology) Either of the two apertures in the calamus of a feather.
5. (space science) A tube connecting an astronaut or spacecraft to the mothership, through which supplies and samples can be transferred.
   The importance of the visual analyzer is further increased when the cosmonaut is in free space with only the slight support of an umbilicus. 1966, Aerospace Technology Division, Soviet Biotechnology and Bioastronautics: Report, Library of Congress, page 10
   Penetrators will be connected by an umbilicus to an afterbody containing imaging and meteorological instruments. 1977, James W. Head, United States. National Aeronautics, Space Administration, Significant achievements in the planetary geology program, 1975-1976
   How about a 270 mile tether to an orbiting satellite? Oh, you'd like that, wouldn't you? Frank! Prepare to receive the umbilicus! 1994, Michael J. Nelson (head writer), "Girls Town", episode 601, Mystery Science Theater 3000
   Ninety minutes into the twenty-six hour flight, Leonov opened the outer hatch and pushed himself out to the end of his 17-foot umbilicus — becoming the first man to walk in space. 2013, Treion Muller, Matthew Murdoch, The Webinar Manifesto: Never Design, Deliver, or Sell Lousy Webinars Again!, RosettaBooks
6. (geometry, obsolete) One of the foci of an ellipse or other curve.
7. (geometry) A point of a surface at which the curvatures of the normal sections are all equal to each other.
   A sphere may be osculatory to the surface in every direction at an umbilicus.
8. (historical) An ornamented or painted ball or boss fastened at each end of the stick on which manuscripts were rolled.
   The ends of the umbilicus were called cornua (i.e. horns) in Latin, and were usually adorned with some pretty device 1763, William Massey, The Origin and Progress of Letters