From WordNet (r) 2.0 (August 2003) [wn]:
monitor
n 1: display consisting of a device that takes signals from a
computer and displays them on a CRT screen [syn:
monitoring device]
2: someone who supervises (an examination) [syn: proctor]
3: someone who gives a warning so that a mistake can be avoided
[syn: admonisher, reminder]
4: an iron-clad vessel built by Federal forces to do battle
with the Merrimac [syn: Monitor]
5: electronic equipment that is used to check the quality or
content of electronic transmissions
6: a piece of electronic equipment that keeps track of the
operation of a system continuously and warns of trouble
7: any of various large tropical carnivorous lizards of Africa
and Asia and Australia; fabled to warn of crocodiles [syn:
monitor lizard, varan]
v : keep tabs on; keep an eye on; keep under surveillance [syn:
supervise, ride herd on]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Monitor \Mon"i*tor\, n. [L., fr. monere. See Monition, and cf.
Mentor.]
1. One who admonishes; one who warns of faults, informs of
duty, or gives advice and instruction by way of reproof or
caution.
[1913 Webster]
You need not be a monitor to the king. --Bacon.
[1913 Webster]
2. Hence, specifically, a pupil selected to look to the
school in the absence of the instructor, to notice the
absence or faults of the scholars, or to instruct a
division or class.
[1913 Webster]
3. (Zool.) Any large Old World lizard of the genus Varanus;
esp., the Egyptian species (Varanus Niloticus), which is
useful because it devours the eggs and young of the
crocodile. It is sometimes five or six feet long.
[1913 Webster]
4. [So called from the name given by Captain Ericson, its
designer, to the first ship of the kind.] An ironclad war
vessel, very low in the water, and having one or more
heavily-armored revolving turrets, carrying heavy guns.
[1913 Webster]
5. (Mach.) A tool holder, as for a lathe, shaped like a low
turret, and capable of being revolved on a vertical pivot
so as to bring successively the several tools in holds
into proper position for cutting.
[1913 Webster]
6. A monitor nozzle.
[Webster 1913 Suppl.]
Monitor top, the raised central portion, or clearstory, of
a car roof, having low windows along its sides.
[1913 Webster]
From The Free On-line Dictionary of Computing (19 Sep 2003) [foldoc]:
monitor
1. A cathode-ray tube and associated electronics connected
to a computer's video output. A monitor may be either
monochrome (black and white) or colour (RGB). Colour
monitors may show either digital colour (each of the red,
green and blue signals may be either on or off, giving eight
possible colours: black, white, red, green, blue, cyan,
magenta and yellow) or analog colour (red, green and blue
signals are continuously variable allowing any combination to
be displayed). Digital monitors are sometimes known as TTL
because the voltages on the red, green and blue inputs are
compatible with TTL logic chips.
See also gamut, multisync, visual display unit.
2. A programming language construct which encapsulates
variables, access procedures and initialisation code within an
abstract data type. The monitor's variable may only be
accessed via its access procedures and only one process may be
actively accessing the monitor at any one time. The access
procedures are critical sections. A monitor may have a
queue of processes which are waiting to access it.
3. A hardware device that measures electrical events such as
pulses or voltage levels in a digital computer.
4. To oversee a program during execution. For example, the
monitor function in the Unix C library enables profiling
of a certain range of code addresses. A histogram is produced
showing how often the program counter was found to be at
each position and how often each profiled function was called.
Unix man page: monitor(3).
5. A control program within the operating system that
manages the allocation of system resources to active
programs.
6. A program that measures software performance.