- A one-sided topologic surface having no inside or outside, formed by inserting the small open end of a tapered tube through the side of the tube and making it contiguous with the larger open end.克莱因瓶：一种既没有内表面也没有外表面的单侧拓扑面，它是通过把逐渐变细的管子的小的开端插入管壁并使它与大的开端相连而形成的
- After Felix Klein (1849-1925), German mathematician 源自弗利克斯 克莱因 (1849-1925年），德国数学家
- contortionist
- contortionists
- contorts
- contour
- contoured
- contour feather
- contouring
- contour line
- contour map
- contours
- contr.
- contra
- contra-
- contraband
- contrabanded
- contrabanding
- contrabands
- contrabass
- contrabasses
- contrabassoon
- contraception
- contraceptions
- contraceptive
- contraceptives
- Contra Costa College