The short verse of the Psalms chanted at Vespers, Matins and before the Epistle at other Services.

short verse generally chanted as an introduction to a reading from holy scripture.

These are verses from the Psalter sung immediately before Scripture Lessons, primarily at Liturgy, Vespers and Matins. [Except for Feasts and during Great Lent, the Scripture Lessons themselves have generally fallen out of use at Vespers.] The Prokeimenon sung immediately before the Gospel Lesson is called the Alleluia.