Postscript

PostScript (so capitalized) refers to a programming language: see PostScript. Since computer hackers rarely engage in written communication other than e-mail, in their mouths the word almost always refers to the programming language.

In the mouths of everyone else, a postscript is a sentence, paragraph, or occasionally many paragraphs added, often hastily and incidentally, after the signature of a letter or (sometimes) the main body of an essay or book. In a book or essay, a more carefully-composed addition is called an afterword, e.g., for a second edition, an afterword, not usually called a postscript, is written in response to critical remarks on the first edition. The word has, poetically, been used to refer to any sort of addendum to some main work, even if not attached to a main work, as in Soren Kierkegaard's book titled Concluding Unscientific Postscript.

In the age of e-mail, postscripts have become unnecessary: if one has something to add to a letter, one simply edits the e-mail before sending, while if one has something to add after a letter has been sent, an entirely new e-mail must be created.

Cf. other publishing terms: afterword; appendix; addendum.