Tenebrae
Pronunciation : Ten"e*br
Part of Speech : n.
Etymology : [L., pl., darkness.] (R. C. Ch.)
Definition : Defn: The matins and lauds for the last three days of Holy Week, commemorating the sufferings and death of Christ, -- usually sung on the afternoon or evening of Wednesday, Thursday, and Friday, instead of on the following days.
Source : Webster's Unabridged Dictionary, 1913