What do you call events that signify a specific year on the timeline?

This photo is forever associated with the year 1973. It's a signifier for 1973 in my memory.

This photo is forever associated with the year 1973. It’s a signifier for 1973 in my memory.

Not unexpectedly, some events in my life stand out as more important and/or memorable than others, and are therefore worth being placed on my personal timeline.

I’m thinking of events like when I began school, when I was married, when my children were born, when I defended my PhD, when I landed a new job, and so on and so forth. There are maybe a couple of hundred events of that kind altogether.

As Ken Caneva points out, these are examples of typical ‘milestones’. But I’m also thinking about seemingly less important events that are usually not thought of in terms of ‘milestones’, such as my telling Larry Holmes at the HSS meeting in New Orleans in 1994 that I was relieved by the death of Niels Jerne. It took five minurtes, and it’s definitely not a turning point in my life, but it nevertheless forever imprinted in my memory as an event attached to the year of 1994. Or like listening to Sgt Pepper’s Lonely Heart Club Band was a ‘marker’ event of my 1967. These events are signifiers (markers, cues) for a particular year and function as a kind of signposts on the timeline.

So it’s not just ‘milestones’, what’s the best generic term for such events? I have made some searches on the net and in the literature and cannot find a good generic term.

Could one call them ‘signal events’? Or ‘signifying events’? Or ‘autobiographical cues’? Or ‘signposts’? Or perhaps ‘bio-markers’ (although there’s of course a risk of confusion with biomarkers in the biomedical sense)?