Frequency: The word is one of the 700 most common words in English.
Note: 'Their' is the third person plural possessive determiner.
1.
You use ~ to indicate that something belongs or relates to the group of people, animals, or things that you are talking about.
Janis and Kurt have announced ~ engagement...
Horses were poking ~ heads over ~ stall doors.
DET
2.
You use ~ instead of ‘his or her’ to indicate that something belongs or relates to a person without saying whether that person is a man or a woman. Some people think this use is incorrect.
Every member will receive ~ own ‘Welcome to Labour’ brochure.
DET