In language, an archaism is a word, a sense of a word, or a style of speech or writing that belongs to a historical epoch beyond living memory, but that has survived in a few practical settings or affairs. Lexical archaisms are single archaic words or expressions used regularly in an affair (e.g. religion or law) or freely; literary archaism is the survival of archaic language in a traditional literary text such as a nursery rhyme or the deliberate use of a style characteristic of an earlier age—for example, in his 1960 novel The Sot-Weed Factor, John Barth writes in an 18th-century style. Archaic words or expressions may have distinctive emotional connotations—some can be humorous (forsooth), some highly formal (What say you?), and some solemn (With thee do I plight my troth). The word archaism is from the Ancient Greek: ἀρχαϊκός, archaïkós, 'old-fashioned, antiquated', ultimately ἀρχαῖος, archaîos, 'from the beginning, ancient'.
A distinction between archaic and obsolete words and word senses is widely used by dictionaries. An archaic word or sense is one that still has some current use but whose use has dwindled to a few specialized contexts, outside which it connotes old-fashioned language. In contrast, an obsolete word or sense is one that is no longer used at all. A reader encounters them when reading texts that are centuries old. For example, the works of Shakespeare are old enough that some obsolete words or senses are encountered therein, for which glosses (annotations) are often provided in the margins.
