English is an ever-changing language that has evolved over centuries. As the world changes, so does the English language, adding new words and discarding others. Archaisms belong to a category of words that have survived against all odds.
An archaism is a word, phrase or literary device that is no longer commonly used, or is used only in very specific instances. The original meaning of an archaism is often lost in antiquity. An archaism is distinct from an obsolete word, in that the archaism is still occasionally used while the obsolete word is no longer used in any context. Some examples of archaisms are thou, unhand and vim as in vim and vigor. Note that the examples thou and unhand are usually employed to evoke an old-fashioned atmosphere, making these literary archaisms. The vim in the term vim and vigor is a lexical archaism or fossil word, an archaism that is used in a narrow or very specific instance. Archaisms are most commonly found in older literary works such as the sonnets and plays of Shakespeare or nursery rhymes, in the law, in religious terms and geographical names. Archaisms are interesting examples of the constant evolution of the English language, as well as a window on the past.