Finding Truth Forum Nomenclature and Identity

I am in the process of working on a piece exploring the reliance of nomenclature to identity. I am wondering about it in both psychological terms as well as writing stylistic terms. If we alter or refine the definition of a concept or word, does it really alter what the object or concept that had been named that? This gets even trickier when the object is sentient. Do the people's opinions really alter what you think about yourself? Is sanity subjective or objective? If objective, who decides what the guidelines are and what happens to those that live in the tidal changes in the definitions? I don't really have the answers to these ideas or really firm opinions yet, I am letting my characters develop and answer these questions as they go along... Anyone with opinions or ideas on what roads might be traveled and in what truck-stop urinal might have the wisdom scrawled in poor penmanship under an obscene drawing?