( n. )
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. Called also umbilic.
( n. )
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. Called also umbilic.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012