Terce, or Third Hour, is a fixed time of prayer of the Divine Office of almost all the Christian liturgies. It consists mainly of psalms and is said at 9 a.m. Its name comes from Latin and refers to the third hour of the day after dawn.
Much of this article is adapted from the Catholic Encyclopedia of 1917. Note that it describes the office before the reforms of the Second Vatican Council. The psalm numbers are given first according to the Septuagint (followed by the Masoretic or "King James" numbering in parentheses).
Read more about Terce: Origin, Development, Symbolism, Comparison To Other Rites, Eastern Christian Office