Archaism

In language, an archaism (from the Greek: ἀρχαϊκός, archaïkós, 'old-fashioned, antiquated', ultimately ἀρχαῖος, archaîos, 'from the beginning, ancient') is the use of a form of speech or writing that is no longer current. This can either be done deliberately (to achieve a specific effect) or as part of a specific jargon (for example in law) or formula (for example in religious contexts). Many nursery rhymes contain archaisms. Archaic elements that occur only in certain fixed expressions (for example 'be that as it may') are not considered to be archaisms.