Punctuation is everything in written language other than the actual letters or numbers, including punctuation marks (listed at right), inter-word spaces and indentation.
Punctuation marks are symbols that correspond to neither phonemes (sounds) of a language nor to lexemes (words and phrases), but which serve to indicate the structure and organization of writing, as well as intonation and pauses to be observed when reading it aloud. See orthography.
In English, punctuation is vital to disambiguate the meaning of sentences. For example, "woman, without her man, is nothing," and "woman: without her, man is nothing," have greatly different meanings, as do "eats shoots and leaves" and "eats, shoots and leaves."
The rules of punctuation vary with language, location, register and time, and are constantly evolving. Certain aspects of punctuation are stylistic and are thus the author's (or editor's) choice. Tachygraphic language forms, such as those used in online chat and text messages, may have wildly different rules.
The earliest writing had no capitalization, no spaces and no punctuation marks. This worked as long as the subject matter was restricted to a limited range of topics (for example, writing was initially used for recording business transactions). Expanding the use of writing to more abstract concepts required some way to disambiguate meanings. Until the 18th century, punctuation was principally an aid to reading aloud; after that time its development was as a mechanism for ensuring that the text made sense when read silently.
The oldest known document that uses punctuation is the Mesha Stele (9th century BC). This employs points between the words and horizontal strokes between the sense section as punctuation.
The Greeks were using punctuation marks consisting of vertically arranged dots - usually two (c.f. the modern colon) or three - in around the 5th century BC. Greek playwrights (e.g., Euripides and Aristophanes) used symbols to...