Answer:

twi

Answer	Crossword Clue
TWI	..-night doubleheader
TWI	Starter on nighter
TWI	Double (prefix)

TWI	Light starter?
TWI	Light opening?
TWI	... -night doubleheader
TWI	..-nighter: baseball event
TWI	Light or night opening
TWI	Light beginning
TWI	Light head?
TWI	Prefix with light

TWI	Bi- equivalent
TWI	Prefix with light or night
TWI	Light or night beginning
TWI	Light starter
TWI	Light or night starter
TWI	Prefix for night or light
TWI	Prefix with night or light
TWI	Lead-in for light or night

TWI	...-nighter (baseball event)
TWI	Prefix with "light"
TWI	Night double-header starter
TWI	Night or light preceder
TWI	Opening for light?
TWI	Prefix for light
TWI	...-night doubleheader
TWI	Start to light?

TWI	Light lead-in
TWI	Suffix for light
TWI	..-night (like some doubleheaders)
TWI	Light preceder
TWI	Prefix for light or night
TWI	Light or night preceder
TWI	Prefix with light and night
TWI	Double: Prefix.

TWI	Prefix meaning double.
TWI	Prefix with light and night.
TWI	Prefix with light or night.
TWI	Early evening: Abbr.
TWI	Prefix with night and light.