Definition of omphalomancy in US English:

omphalomancy

noun

  • Divination by the navel, especially the art or practice of divining the number of future children a woman is to have by counting the number of knots on the umbilical cord of a baby born to her (obsolete rare); (in extended use) the art or skill of predicting or estimating numbers of people (rare).

Origin

Mid 17th century; earliest use found in John Gaule (1603/4–1687), Church of England clergyman and author. From omphalo- + -mancy; compare French † omphalomantie, omphalomancie.