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hemicyclium

American  
[hem-i-sik-lee-uhm] / ˌhɛm ɪˈsɪk li əm /

noun

  1. a sundial in the form of a concave quarter sphere having a rodlike gnomon lying within one radius and marked on its surface with arcs that lie in the same plane as the gnomon.


Etymology

Origin of hemicyclium

From Latin; hemicycle