Answer:

MID

Answer	Crossword Clue
MID	Central
MID	Section opener?
MID	Amongst

MID	Central: Prefix
MID	Surrounded by
MID	Start for day or night
MID	Halfway, for short
MID	Halfway
MID	Prefix for day or night
MID	...-cap stocks
MID	Near the center of

MID	...-Cities (Dallas-Fort Worth suburbs)
MID	Near the center
MID	Prefix with day or week
MID	Prefix with life or wife
MID	Prefix with shipman
MID	Range opening
MID	Term opening
MID	Preix with wife or way

MID	Prefix with summer and winter
MID	Prefix with day or way
MID	Prefix with term or life
MID	Day's beginning?
MID	Lead-in for life or size
MID	Prefix with morning or afternoon
MID	Prefix for field or stream
MID	In the thick of

MID	Not pre- or post-
MID	Start of night or day?
MID	Prefix for night or life
MID	Prefix for week or afternoon
MID	In between
MID	Term start?
MID	Section or stream starter
MID	Summer's beginning?

MID	Wife introduction?
MID	Start of a life crisis?
MID	Prefix for life or wife
MID	Prefix with night or day
MID	Summer or winter lead-in