turning point
US /ˈtɜːrnɪŋ pɔɪnt/
UK /ˈtɜːrnɪŋ pɔɪnt/

1.
tournant, point décisif
a time at which a decisive change in a situation occurs, especially one with important consequences
:
•
The invention of the internet was a turning point in human history.
L'invention d'Internet a été un tournant dans l'histoire de l'humanité.
•
His decision to move abroad marked a significant turning point in his life.
Sa décision de déménager à l'étranger a marqué un tournant important dans sa vie.