From WordNet (r) 2.0 (August 2003) [wn]:
guard
n 1: a person who keeps watch over something or someone
2: the person who plays that position on a football team; "the
left guard was injured on the play"
3: a device designed to prevent injury [syn: safety, {safety
device}]
4: a posture of defence in boxing or fencing; "keep your guard
up"
5: the person who plays the position of guard on a basketball
team
6: a group of men who escort and protect some important person
[syn: bodyguard]
7: a precautionary measure warding off impending danger or
damage or injury etc.; "he put an ice pack on the injury
as a precaution"; "an insurance policy is a good
safeguard"; "we let our guard down" [syn: precaution,
safeguard]
8: the duty of serving as a sentry; "he was on guard that
night" [syn: guard duty, sentry duty, sentry go]
9: a position on the line of scrimmage; "guards must be good
blockers"
10: a position on a basketball team
v 1: to keep watch over; "there would be men guarding the horses"
2: watch over or shield from danger or harm; protect; "guard my
possessions while I'm away" [syn: ward]
3: protect against a challenge or attack; "Hold that position
behind the trees!"; "Hold the bridge against the enemy's
attacks" [syn: defend, hold]
4: take precautions in order to avoid some unwanted
consequence; "guard against becoming too friendly with the
staff"; "guard against infection"
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Guard \Guard\ (g[aum]rd), v. i.
To watch by way of caution or defense; to be cautious; to be
in a state or position of defense or safety; as, careful
persons guard against mistakes.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Guard \Guard\, n. [OF. guarde, F. garde; of German origin; cf.
OHG. wart, warto, one who watches, warta a watching, Goth.
wardja watchman. See Guard, v. t.]
[1913 Webster]
1. One who, or that which, guards from injury, danger,
exposure, or attack; defense; protection.
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His greatness was no guard to bar heaven's shaft.
--Shak.
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2. A man, or body of men, stationed to protect or control a
person or position; a watch; a sentinel.
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The guard which kept the door of the king's house.
--Kings xiv.
27.
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3. One who has charge of a mail coach or a railway train; a
conductor. [Eng.]
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4. Any fixture or attachment designed to protect or secure
against injury, soiling, or defacement, theft or loss; as:
(a) That part of a sword hilt which protects the hand.
(b) Ornamental lace or hem protecting the edge of a
garment.
(c) A chain or cord for fastening a watch to one's person
or dress.
(d) A fence or rail to prevent falling from the deck of a
vessel.
(e) An extension of the deck of a vessel beyond the hull;
esp., in side-wheel steam vessels, the framework of
strong timbers, which curves out on each side beyond
the paddle wheel, and protects it and the shaft
against collision.
(f) A plate of metal, beneath the stock, or the lock
frame, of a gun or pistol, having a loop, called a
bow, to protect the trigger.
(g) (Bookbinding) An interleaved strip at the back, as in
a scrap book, to guard against its breaking when
filled.
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5. A posture of defense in fencing, and in bayonet and saber
exercise.
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6. An expression or admission intended to secure against
objections or censure.
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They have expressed themselves with as few guards
and restrictions as I. --Atterbury.
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7. Watch; heed; care; attention; as, to keep guard.
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8. (Zool.) The fibrous sheath which covers the phragmacone of
the Belemnites.
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Note: Guard is often used adjectively or in combination; as,
guard boat or guardboat; guardroom or guard room; guard
duty.
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Advanced guard, Coast guard, etc. See under Advanced,
Coast, etc.
Grand guard (Mil.), one of the posts of the second line
belonging to a system of advance posts of an army.
--Mahan.
Guard boat.
(a) A boat appointed to row the rounds among ships of war
in a harbor, to see that their officers keep a good
lookout.
(b) A boat used by harbor authorities to enforce the
observance of quarantine regulations.
Guard cells (Bot.), the bordering cells of stomates; they
are crescent-shaped and contain chlorophyll.
Guard chamber, a guardroom.
Guard detail (Mil.), men from a company regiment etc.,
detailed for guard duty.
Guard duty (Mil.), the duty of watching patrolling, etc.,
performed by a sentinel or sentinels.
Guard lock (Engin.), a tide lock at the mouth of a dock or
basin.
Guard of honor (Mil.), a guard appointed to receive or to
accompany eminent persons.
Guard rail (Railroads), a rail placed on the inside of a
main rail, on bridges, at switches, etc., as a safeguard
against derailment.
Guard ship, a war vessel appointed to superintend the
marine affairs in a harbor, and also, in the English
service, to receive seamen till they can be distributed
among their respective ships.
Life guard (Mil.), a body of select troops attending the
person of a prince or high officer.
Off one's guard, in a careless state; inattentive;
unsuspicious of danger.
On guard, serving in the capacity of a guard; doing duty as
a guard or sentinel; watching.
On one's guard, in a watchful state; alert; vigilant.
To mount guard (Mil.), to go on duty as a guard or
sentinel.
To run the guard, to pass the watch or sentinel without
leave.
Syn: Defense; shield; protection; safeguard; convoy; escort;
care; attention; watch; heed.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Guard \Guard\, v. t. [imp. & p. p. Guarded; p. pr. & vb. n.
Gurding.] [OF. guarder, garder, warder, F. garder, fr. OHG.
wart?n to be on the watch, await, G. marten. See Ward, v. &
n., and cf. Guard, n.]
1. To protect from danger; to secure against surprise,
attack, or injury; to keep in safety; to defend; to
shelter; to shield from surprise or attack; to protect by
attendance; to accompany for protection; to care for.
[1913 Webster]
For Heaven still guards the right. --Shak.
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2. To keep watch over, in order to prevent escape or restrain
from acts of violence, or the like.
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3. To protect the edge of, esp. with an ornamental border;
hence, to face or ornament with lists, laces, etc.
The body of your discourse is sometime guarded with
fragments, and the guards are but slightly basted on
neither. --Shak.
[1913 Webster]
4. To fasten by binding; to gird. [Obs.] --B. Jonson.
Syn: To defend; protect; shield; keep; watch.
[1913 Webster]
From The Free On-line Dictionary of Computing (19 Sep 2003) [foldoc]:
guard
<programming> 1. In functional programming, a Boolean
expression attached to a function definition specifying when
(for what arguments) that definition is appropriate.
2. In (parallel) logic programming, a Boolean expression
which is used to select a clause from several alternative
matching clauses.
See Guarded Horn Clauses.
3. In parallel languages, a Boolean expression which
specifies when an message may be sent or received.
(1995-05-09)