absis or apsis, īdis (collat. form ab-sīda, ae, Paul. Ep. 12; cf. Isid. Orig. 15, 8, 7), f., = a(yi/s, lit. a fitting together in a circular form, hence an arch or vault.I.Plin. Ep. 2, 17 (but in Plin. 36, 12, 17, the correct read. is aspidem, v. Sillig ad h. l.). —In a church, the choir, Isid. Orig. 15, 18, 7, and Paul. Ep. 12 (in both of which it is doubtful whether absis, idis, or absida, ae, should be read; cf. Areval upon Isid. l. c.). —II.The circle which a star describes in its orbit, Plin. 2, 18, 16, 79; cf. id. 2, 15, 13, 63.—III.A round dish or bowl, Dig. 34, 2, 19, 6; ib. Fragm. 32, 1.