> for people to hold different definitions of words [...] is the single biggest reason for all arguments in recent human history.

IMO this extremely, extraordinarily true. And in my experience, it's somehow even more true for disagreements among scientists. Even though every scientific field is, in some sense, about defining a shared set of extremely precise jargon. (I recall two very well-respected scientists screaming at each other about the definition of "acidity" for instance)