Definition of "apsis" [ap•sis]

• Architecture An apse. (noun)
• Astronomy The point of greatest or least distance of the orbit of a celestial body from a center of attraction. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In the apsis was a mosaic which represented the Blessed Trinity, and of which in 1512 some remnants were still found."
• "The presbytery was also known as apsis, exedra, concha, designations referring to its form; bema from the fact that it was elevated above the level of the nave and in consequence reached by a stairway of a few steps; tribuna because of its location and general resemblance to the tribunal in civil basilicas whence the magistrates administered justice."
• "This original church was modelled after the ancient Basilica, or hall of justice or of commerce: at one end was an elevated tribunal, and back of this what was called the "apsis," -- a rounded space with arched roof."