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† hēmĭcyclium, ĭi, n.,  =  ἡμικύκλιον, 
- I. a half-circle, semicircle, Vitr. 9, 8, 5; Plin. Ep. 5, 6, 33.
 
- II.  In partic. 
 
- A.  A semicircular recess, with seats, Cic. Lael. 1, 2; Sid. Ep. 2, 2.
 
- B.  A semicircular public place furnished with rows of seats for learned discussions, Suet. Gramm. 17.
 
- C.  A semicircular kind of sundial, Vitr. 9, 8, 1.