Vigil
A vigil is a period of purposeful sleeplessness, an occasion for devotional watching, or an observance.
The word derives from the Latin vigilia meaning "wakefulness" (Greek: pannychis, παννυχίς or agrypnia ἀγρυπνία), and the Italian word vigilia has become generalized in this sense and means "eve" (as in "on the eve of the war").