A cusp is defined as a pointed end where two curves meet, in particular.
It is the meeting and merging points of several thoughts, plans and paths. The point just before the decision is made. It is that point which changes direction and creates history. That moment in the recent past when Roger Federer and Rafael Nadal embraced each other during the 2017 Australian Open Finals. It was the height of excitement, the source of anxiety and suspense. They showed each other and the rest of the world their best side in the epic finals that was – 6-4 3-6 6-1 3-6 6-3.
That moment when Federer had the break through, that moment when Nadal fell short, all at the same moment, that was the cusp.