ˌinstant ˈmessaging BrE AmE noun [uncountable]
a type of service available on the Internet that allows you to quickly exchange written messages with people that you know:
instant messaging services
—instant message noun [countable]
ˌinstant ˈmessaging BrE AmE noun [uncountable]
a type of service available on the Internet that allows you to quickly exchange written messages with people that you know:
instant messaging services
—instant message noun [countable]
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012