hypotrachelium

from The Collaborative International Dictionary of English v.0.48

Gorgerin \Gor`ge*rin"\, n. [F., fr. gorge neck.] (Arch.)
   In some columns, that part of the capital between the
   termination of the shaft and the annulet of the echinus, or
   the space between two neck moldings; -- called also {neck of
   the capital}, and {hypotrachelium}. See Illust. of {Column}.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Hypotrachelium \Hy`po*tra*che"li*um\, n. [L., fr. Gr. ?; ? under
   + ? neck.] (Arch.)
   Same as {Gorgerin}.
   [1913 Webster]