1. a sudden change in a situation
an unexpected/strange turn of events
A 'turn of events' is a change or sudden development in a given situation. You will often hear this as the expression 'a sudden turn of events'. A turn of events might demand a change in strategy, approach or planning in order to deal with it. This is a popular expression that can be used in both social and professional contexts. Similar in meaning to 'a twist' in a story or course of events.