I saw an interesting article on Hacker News today. It was called The Meaning of 'su', and it outlined the author's quest to understand the name of the su command in Unix. It's a great read. He starts with the assumption that su stands for super-user, and then infers that it means switch-user, and, well, it goes on from there. But, there is an assumption behind all of it (and the comments on Hacker News) that really should be explored. The assumption is that things have one meaning.