Answer:

start

Answer	Crossword Clue
START	Kick off
START	Square one
START	Begin

START	Open
START	Set in motion
START	Appropriate word here?
START	Hit the trail
START	Select neighbor, on old controllers
START	Instructions, part 3
START	Set moving
START	Maze word

START	Outset
START	Jerk
START	Maze entrance sign
START	Jump of surprise
START	First word in mazes
START	Boot up
START	Read the first clue?
START	Turn the key

START	Genesis
START	Act surprised
START	What first-stringers do
START	Introduction
START	Betray surprise
START	Get going
START	Proctor's instruction
START	Activate

START	Set into motion
START	Touch off
START	Get cracking
START	Get underway
START	Maze entrance word
START	Sudden movement
START	Onset
START	Involuntary jerk

START	"Boo!" reaction
START	Beginning
START	Found, as a business
START	Square on many board games
START	It may be running or flying