A Word is like a coin. With a particular coin different men at different times purchase goods of the same or very similar value. With a particular word different men at different times designate the same or a very similar value. Every coin in the course of its history is subjected to different changes in value; for the same coin may suddenly obtain more or less in exchange. Exactly thus does the value of a word change; it can at one time denote more, at another less; a more comprehensive or a more restricted concept. And just as for the coin, there comes also for the word the day on which it is “removed from circulation.” As a coin can become valueless, so a word can become senseless, insignificant.