A feast of less importance than a “double” feast. It is so called because the antiphon before each psalm in the Sacred Office is not read in full, and thus is only “half-doubled” for that psalm.
- “semi-double feast”. . CatholicSaints.Info. 23 March 2010. Web. 27 April 2015. <http://catholicsaints.info/semi-double-feast/>