Leaving (noun)

1. An act of departing or leaving.
2. A state of being no longer present.

Origin:

Late 16th century (as a verb in the sense "depart"): from leave + -ing1.

Examples:

1. She left the house after her father's leaving.
2. She was in tears at the thought of his leaving.
3. His leaving for college marks the end of an era.
4. The leaving of the autumn leaves signified the end of fall.
5. The leaving of the troops was seen as a turning point in the war.