A concept that I think is *important* and yet frequently underused is that of *contingency*. For something to be *contingently* true it needs to neither be **necessarily** true or **necessarily** false, or in the language of possible worlds there is at least one world in which it is true and one world in which it isn't.
It's a useful concept outside of the domain of modal logic, though! I think it's one of the more important ideas that I'd like everyone to absorb outside of philosophy: many of the truths of we deal with in our day to day lives are either **contingently true** or at least **not provably necessary**.
"The United States is a country" is a contingent truth, somewhat obviously. But what's not obvious until you sit with it is that even the existence of the idea "something is a country" is, also, only contingently defined. It's not hard to imagine worlds where "country" and "borders" are not concepts that exist, because there's nothing to prove that they're inherent to the world itself. This is the extension of contingent truth that I like to harp on: contingently defined ideas.
Most of our ideas are contingently defined. Some like gender and sexuality I think a lot of people can agree are historical accidents, in part because we can see them changing over time in how they're understood & conceptualized. Others, might be a little more surprising. I remember someone once snarkily saying "what, are you going to claim that *atoms* are a social construct?" and I sat there a moment before I was like "well, yes!". Now before anyone thinks I'm claiming that science isn't describing real things and that reality is whatever we imagine &c. &c. please know that's **not** what I mean.
What I mean is that even scientific ideas like "atoms" are particular explanations of the world that have come about through a series of historical accidents and they're contingently defined. Look at the periodic table, for example. It's an artifact of a time where we thought that there were many different kinds of materials, who could be arranged according to their relative weight and properties in common. It was observed that there were cycles to many of the properties, hence it being called the "periodic" table, and we could arrange columns of like things in ascending mass.
Now, what if, instead, we'd developed the theories of sub-atomic particles much earlier than we did and rather than organizing the periodic table over the course of a couple of hundred years we instead classified "our" atoms as being configurations of protons, neutrons, and electrons---some of which were worthy of names and others weren't. In other words, it'd be the same way in our world we treat all the combinations of quarks to make hadrons.
So, yes, while the physical phenomenon *isn't* a social construct, a contingency, the ways we categorize it are. That's the idea I want to convey. That it's worth thinking about possible worlds, about what things are historic accidents, and how important those contingencies are to the shape of our world **and yet** could be rejected or changed because they have no essential nature.