predella

 
Pronunciation: /prɪˈdɛlə/

noun

  • a step or platform on which an altar is placed.
  • a raised shelf above an altar.
  • a painting or sculpture on this, typically forming an appendage to an altarpiece: [as modifier]: four predella panels by Botticelli

Origin:

mid 19th century: from Italian, literally 'stool'