1. a sudden and positive change
complete a remarkable turnaround
The noun 'turnaround' means a quick or sudden change usually for the better. "We had a great turnaround in fortune after winning the money." "The new CEO initiated a great turnaround for the company."
2. time needed to complete a business process
A 'turnaround' also refers to the amount of time needed to process something or to complete a task. "Can you give me time on the turnaround for that order?"