“Definition” bubbles should be “Flush left, ragged right with a hanging bullet” –and not centered. Centered text is most appropriate on invitations and wedding announcements. Centered justification is hard to read and I should explain why.
The link above is pretty good. But left off one detail:
In English-speaking countries and countries using Latin characters, the eye looks for an invisible edge (at the left) to find the next line down upon returning from the end of a line. This is a readability issue: the pleasure or ease of reading.
Centered text destroys that edge finding capability. There is no straight edge.
Technologists seem to think “Justified (flush left and right)” –where both edges are forced to make invisible edge lines– therefore must be even better. It was impossible before the computer age so it must be more advanced. Right? It makes for pretty type.
But humans prefer a “ragged-right” edge. It’s helpful to maintaining a sense of location on the page for the eye. Thus, again, easier finding of the next line down. Justifying both edges (sameness) ruins our eye’s sense of position. It takes more work to read –an unnecessary strain.
Just because you can do something doesn’t mean you should. It’s all UX in the end.