Definitions of engagement
a battle or period of time during a war; the action of beginning to fight someone
Nations need to define the rules of engagement for acts of cyber-terror.
an agreement between two people to marry; the period of time that two people are engaged before they marry
The couple announced their engagement on Wednesday.
an official arrangement to meet someone or do something at a particular time, especially one that is related to your work
Unfortunately I'll have to miss the meeting as I have a prior engagement.