Yes, and you shouldn't use it either. Do you mean night as in dark conditions or night as in the night time? When does it start, when does it end? Is it a threshold or a discrete night-not night effect?

These questions don't have a right or wrong answer. So don't use the word night, or if you do, define exactly what you mean by it.

yeah but with night there is just some quibbling around the edges, is civil twilight night etc. This is more like reptiles, it's a concept that when you pick at it the concept as popularly used it falls apart (for reptiles you either need to include birds or break it up into at least two groups).

of course night is a scientifically defined concept (which also takes human subjectivity into account). The term in science is "Astronomical night" and it has an exact physical description which can be unambiguously determined through scientific measurement.

comments like yours don't add much value to discussions about race.

I’m not sure that’s accurate.

Can't we?

Where does a color stop being yellow and start being green? This is the classic lumping and splitting debate. It's obvious that the mere existence of multuple options for lumping and splitting doesn't imply there are no meaningful distinctions to be made.

I dislike this obvious and offensive dishonesty. We can define race quite easily: A race is a largely endogamous extended family group. But but but that means you could call Yoruba people a race! Well sure, you can. Just like we can call the English or even the Cornish a race. When the Angle race and the Saxon race became exogamous with respect to each other, their distinction faded and a new Anglo-Saxon race came to be. We can also talk about a British race, by descent from William the Conqueror. I believe the Chinese have a notion of five Chinese races. In fact, the notion of lumping races as continental scale groups is an American innovation that is of dubious anthropological value. Point being that you can lump up to all humans being a single race going back to the first humans or split down to the nuclear family[1]. It's clear to me that both of those extremes aren't very interesting, but they are valid! As for useful places to lump and split, genetic screening is an obvious one. As an example, choosing to split intelligently will allow a health service to save money by avoiding unnecessarily testing for sickle cell disease.

It follows that for two typical individuals of the same race, you have to go less far up their family tree to find a common ancestor than you would for two typical individuals of different races. This effect is considerably more pronounced if you restrict it to common ancestors from before 1492. Of course 1492 isn't the only date where this effect is seen. For just one example, most Britons have a common ancestor from slightly after 1066.

[1] Nuclear meaning no longer able to be split (physicists weakened that metaphor a bit though!).

Edit: The redefinition goes the other way, as can be seen from public domain sources like Webster's where the first sense of race is "The descendants of a common ancestor; a family, tribe, people, or nation, believed or presumed to belong to the same stock; a lineage; a breed."

I will happily agree that the contemporary lowbrow usage of race to mean black people or white people, and I dunno maybe let's lump everyone else together as asian except some white or black people are hispanic instead doesn't even rise to the level of being childishly stupid.