Prologue (before the main event) - the Story - Epilogue (after the main event):
Dawn (before the main event) - Daylight/Daytime - Dusk (after the main event.)
Twilight come from Twilight = two + light (probably the light of the day (the sun) and the light of the night (the moon)
1. The light diffused by the reflection of the sun's rays from the atmosphere before sunrise, and after sunset; the period during which this prevails between daylight and darkness.
c1440 Promptorium Parvulorum 505/1 Twylyghte, be-twyx þe day and þe nyghte, or nyghte and þe day, hesperus.
1796 J. Morse Amer. Universal Geogr. (new ed.) I. 52 The twilight is that faint light which opens the morning by little and little in the east, before the sun rises; and gradually shuts in the evening in the west, after the sun is set.
b. spec. Most commonly applied to the evening twilight, from sunset to dark night.
1412–20 J. Lydgate tr. Hist. Troy i. 2733 In þe twyliȝt whan þe day gan fade. [In the twilight when the day[light] began to fade.]
1836 W. Irving Astoria III. xlviii. 99 A chasm that looked dark and frightful in the gathering twilight.
c. Morning twilight, which lasts from daybreak to sunrise.
c1440 Promptorium Parvulorum 505/1 Twye lyghte, be-fore the day, diluculum.
1845 R. Browning How they brought Good News in Bells & Pomegranates No. VII: Dramatic Romances & Lyrics iii. 3 'Twas moonset at starting; but while we drew near Lokeren, the cocks crew and twilight dawned clear.