As the root of the word suggests, archaism means using words, phrases, or expressions which are out of date. According to the definition of archaism, such words are used in writing or speech to give the written or spoken content an artistic appeal and a touch of the old times.
Some archaic words have been a part of our traditions since long and are in common use even today. For example, the vow, “With this ring I thee wed.” is a part of wedding ceremonies. Here, the word thee is an archaic word that is used only in this special context. It is not used normally as it is considered outdated.
Archaic diction can be encountered in law, poetry, philosophy, and science. For example, in law, the words like hereunto and thereof are used. However, examples of archaism are more commonly found in literature.
In literature, archaism can be used to emphasize ideas. As archaic words aren’t used commonly, they attract attention. These words may be used to give a piece of writing the flavor of olden times. They can also be used to bring irony or humor.