Klein bottle

plural Klein bottles

1. mathematicsThe closed manifold obtained by identifying the boundary components of the annulus so that the resultant surface is nonorientable.

   At this level Atman and Brahman are like a Klein bottle or a Möbius strip: there is no edge where one can say that this is Atman, but this is Brahman.

   1981, William Irwin Thompson, The Time Falling Bodies Take to Light: Mythology, Sexuality and the Origins of Culture, London: Rider/Hutchinson & Co., page 222

2. A physical bottle, usually of blown glass, made to resemble said shape.