Definition of "Opening" :

noun: the first of a series of actions

noun: the act of opening something

"The ray of light revealed his cautious opening of the door."

noun: becoming open or being made open

"The opening of his arms was the sign I was waiting for."

noun: a recognized sequence of moves at the beginning of a game of chess

"He memorized all the important chess openings."

noun: an entrance equipped with a hatch; especially a passageway between decks of a ship

noun: a vacant or unobstructed space that is man-made

"They left a small opening for the cat at the bottom of the door."

noun: an aperture or hole that opens into a bodily cavity

noun: a possible alternative

noun: the initial part of the introduction

"The opening established the basic theme."

noun: the first performance (as of a theatrical production)

"The opening received good critical reviews."

noun: a ceremony accompanying the start of some enterprise

noun: an open or empty space in or between things

"There was a small opening between the trees."

noun: opportunity especially for employment or promotion

"There is an opening in the sales department."

adjective: first or beginning

"The memorable opening bars of Beethoven's Fifth."