[with sing. or pl. v.] a Holy Week night service (Wednesday through Friday), formerly widely observed in the Western Church, consisting of group recitation of Matins and Lauds of the following day in commemoration of Christ's death and burial
Origin of TenebraeL, plural , shadows, darkness: see temerity
plural nounused with a sing. or pl. verb Roman Catholic Church
The office of matins and lauds sung on the last three days of Holy Week, with a ceremony of candles.
Origin of TenebraeMedieval Latin from Latin tenebrae darkness
Latin tenebrae shadows, darkness.