Relativity is the word for how things only have importance in relation to other things. In physics, relativity refers to Einstein's theory that time and space are not absolute.
If you believe there are absolute, correct answers to everything, you probably don't like relativity, which is the opposite of absolutism. According to relativity, things aren't good or bad in themselves; they only have significance in relation to other things. In physics, relativity is about how even time and space aren't absolute, objective facts. For example, time partially depends on our perceptions of it: time is relative.