<language, text> An {SGML}, {HTML}, or {XML} {token}
	representing the beginning (start tag: "<p ...>") or end (end
	tag: "</p>") of an {element}.  In normal SGML {syntax} (and
	always in {XML}), a tag starts with a "<" and ends with an
	">".

	In {HTML} jargon, the term "tag" is often used for an
	"{element}".

	(2001-01-31)

<convention, data> A string unique to a time duration of 24
	hours between 2 successive midnights defined by the local time
	zone.  The specific representation of a date will depend on
	which calendar convention is in force; e.g., Gregorian,
	Islamic, Japanese, Chinese, Hebrew etc. as well as local
	ordering conventions such as UK: day/month/year, US:
	month/day/year.

	Inputting and outputting dates on computers is greatly
	complicated by these {localisation} issues which is why they
	tend to operate on dates internally in some unified form such
	as seconds past midnight at the start of the first of January
	1970.

	Many software and hardware representations of dates allow only
	two digits for the year, leading to the {year 2000} problem.

	{Unix manual page}: date(1), ctime(3).

	(1997-07-11)

<hardware> To press and release a {button} on a {mouse} or
	other {pointing device}.  This generates an {event}, also
	specifying the screen position, which is processed by the
	{window manager} or {application program}.  On a mouse with
	more than one button, the unqualified term usually implies
	pressing the left-most button (with the right index finger),
	other buttons would be qualified, e.g. "{right-click}".
	{Keyboard} modifiers may also be used, e.g. "shift-click",
	meaning to hold down the shift key on the keyboard while
	clicking the mouse button.

	If the mouse moves while the button is pressed then this is a
	{drag}.

	(1995-03-14)

1. <data, graphics> Data representing a two-dimensional scene.
	A digital image is composed of {pixels} arranged in a
	rectangular array with a certain height and width.  Each pixel
	may consist of one or more {bits} of information, representing
	the brightness of the image at that point and possibly
	including colour information encoded as {RGB} triples.

	{Images} are usually taken from the real world via a {digital
	camera}, {frame grabber}, or {scanner}; or they may be
	generated by computer, e.g. by {ray tracing} software.

	See also {image formats}, {image processing}.

	(1994-10-21)

	2. <mathematics> The image (or range) of a {function} is the
	set of values obtained by applying the function to all
	elements of its {domain}.  So, if f : D -> C then the set f(D)
	= \{ f(d) | d in D \} is the image of D under f.  The image is
	a subset of C, the {codomain}.

	(2000-01-19)

1. To prepare to read or write a file.  This usually involves
	checking whether the file already exists and that the user has
	the necessary authorisation to read or write it.  The result
	of a successful open is usually some kind of {capability}
	(e.g. a {Unix} {file descriptor}) - a token that the user
	passes back to the system in order to access the file without
	further checks and finally to close the file.

	2. Abbreviation for "open (or left) parenthesis" - used when
	necessary to eliminate oral ambiguity.  To read aloud the LISP
	form (DEFUN FOO (X) (PLUS X 1)) one might say: "Open defun
	foo, open eks close, open, plus eks one, close close."

	3. Non-proprietary.  An open {standard} is one which can be
	used without payment.

	[{Jargon File}]

	(1995-01-31)

<software> Instructions for a computer in some programming
	language, often {machine language}.  The word "code" is often
	used to distinguish instructions from {data} (e.g. "The code
	is marked 'read-only'") whereas "{software}" is used in
	contrast with "{hardware}" and may consist of more than just
	code.

	(2000-04-08)

See also {complete graph}, {complete inference system},
	{complete lattice}, {complete metric space}, {complete partial
	ordering}, {complete theory}.

	[1. or 2. or both?]

	(1996-04-24)