umbilicus

Borrowed from Latin umbilīcus (“navel”).

• IPA^(key): /ˌʌmˈbɪlɪkəs/
• (UK) IPA^(key): /ʌmbɪˈlʌɪkəs/

umbilicus (plural umbilici or umbilicuses)

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.
   • 1966, Aerospace Technology Division, Library of Congress, Soviet Biotechnology and Bioastronautics: Report, page 10:

     The importance of the visual analyzer is further increased when the cosmonaut is in free space with only the slight support of an umbilicus.

   • 1977, James W. Head, United States. National Aeronautics and Space Administration, Significant achievements in the planetary geology program, 1975-1976

     Penetrators will be connected by an umbilicus to an afterbody containing imaging and meteorological instruments.

   • 1994, Michael J. Nelson (head writer), "Girls Town", episode 601, Mystery Science Theater 3000

     How about a 270 mile tether to an orbiting satellite? Oh, you'd like that, wouldn't you? Frank! Prepare to receive the umbilicus!

   • 2013, Treion Muller, Matthew Murdoch, The Webinar Manifesto: Never Design, Deliver, or Sell Lousy Webinars Again!, RosettaBooks →ISBN

     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.

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.

   (Can we find and add a quotation of Dr. W. Smith to this entry?)

• (navel): omphalos
• (navel): omphalus

From Proto-Indo-European *h₃m̥bʰ-Vl-īkos, *h₃nobʰilos, from *h₃nebʰ- (“navel”).

• (Classical) IPA^(key): /um.biˈliː.kus/, [ʊm.bɪˈliː.kʊs]

umbilīcus m (genitive umbilīcī); second declension

1. (anatomy) A navel.
2. The middle or center.
3. The ornamented end of a scroll.

Second declension.

• umbilicus in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• umbilicus in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• umbilicus in Gaffiot, Félix (1934) Dictionnaire Illustré Latin-Français, Hachette
• umbilicus in Harry Thurston Peck, editor (1898) Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
• umbilicus in William Smith et al., editor (1890) A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin