I fail to see how your citation of the dictionary supports your use of event as the history of the object's or pulse of lights trajectory through space-time. It does however, in the sole sense qualified for theoretical physics, support out usage as a zero-dimensional element of space-time geometry:
http://www.merriam-webster.com/dictionary/event
Event; something that happens.
Does this definition not describe a photon that propagates along a linear path from one point to another? Is that not something that happened?
Not trying to be a wise-ass, just giving you an honest laymen use of the word "event" as I have always used it.