Do you know these two all important nouns?
The MACD stands for moving average, convergence, divergence.
It is a tool used in graphs to plot moving averages and understand the projected moves, whether rising, falling or somewhere in between.
So, to cut to the point. Convergence is when your two lines are moving together. Divergence is when they are moving apart.
We can use these words as verbs.
E.g. The lines are converging / diverging.
When you use this phrasal verb come together, the verb to converge is the equivalent meaning. It is more formal, scientific.