Tide n.
 1. Time; period; season. [Obsoles.] “This lusty summer's tide.”
    And rest their weary limbs a tide.   --Spenser.
 Which, at the appointed tide,
 Each one did make his bride.   --Spenser.
    At the tide of Christ his birth.   --Fuller.
 2. The alternate rising and falling of the waters of the ocean, and of bays, rivers, etc., connected therewith. The tide ebbs and flows twice in each lunar day, or the space of a little more than twenty-four hours. It is occasioned by the attraction of the sun and moon (the influence of the latter being three times that of the former), acting unequally on the waters in different parts of the earth, thus disturbing their equilibrium. A high tide upon one side of the earth is accompanied by a high tide upon the opposite side. Hence, when the sun and moon are in conjunction or opposition, as at new moon and full moon, their action is such as to produce a greater than the usual tide, called the spring tide, as represented in the cut. When the moon is in the first or third quarter, the sun's attraction in part counteracts the effect of the moon's attraction, thus producing under the moon a smaller tide than usual, called the neap tide.
 Note: ☞ The flow or rising of the water is called flood tide, and the reflux, ebb tide.
 3. A stream; current; flood; as, a tide of blood. “Let in the tide of knaves once more; my cook and I'll provide.”
 4. Tendency or direction of causes, influences, or events; course; current.
 There is a tide in the affairs of men,
 Which, taken at the flood, leads on to fortune.   --Shak.
 5. Violent confluence. [Obs.]
 6. Mining The period of twelve hours.
 Atmospheric tides, tidal movements of the atmosphere similar to those of the ocean, and produced in the same manner by the attractive forces of the sun and moon.
 Inferior tide. See under Inferior, a.
 To work double tides. See under Work, v. t.
 Tide day, the interval between the occurrences of two consecutive maxima of the resultant wave at the same place. Its length varies as the components of sun and moon waves approach to, or recede from, one another. A retardation from this cause is called the lagging of the tide, while the acceleration of the recurrence of high water is termed the priming of the tide. See Lag of the tide, under 2d Lag.
 Tide dial, a dial to exhibit the state of the tides at any time.
 Tide gate. (a) An opening through which water may flow freely when the tide sets in one direction, but which closes automatically and prevents the water from flowing in the other direction. (b) Naut. A place where the tide runs with great velocity, as through a gate.
 Tide gauge, a gauge for showing the height of the tide; especially, a contrivance for registering the state of the tide continuously at every instant of time. --Brande & C.
 Tide lock, a lock situated between an inclosed basin, or a canal, and the tide water of a harbor or river, when they are on different levels, so that craft can pass either way at all times of the tide; -- called also guard lock.
 Tide mill. a A mill operated by the tidal currents. (b) A mill for clearing lands from tide water.
 Tide rip, a body of water made rough by the conflict of opposing tides or currents.
 Tide table, a table giving the time of the rise and fall of the tide at any place.
 Tide water, water affected by the flow of the tide; hence, broadly, the seaboard.
 Tide wave, or  Tidal wave, the swell of water as the tide moves. That of the ocean is called primitive; that of bays or channels derivative.  See also tidal wave in the vocabulary. --Whewell.
 Tide wheel, a water wheel so constructed as to be moved by the ebb or flow of the tide.
 Guard, n.
 1. One who, or that which, guards from injury, danger, exposure, or attack; defense; protection.
    His greatness was no guard to bar heaven's shaft.   --Shak.
 2. A man, or body of men, stationed to protect or control a person or position; a watch; a sentinel.
    The guard which kept the door of the king's house.   --Kings xiv. 27.
 3. One who has charge of a mail coach or a railway train; a conductor. [Eng.]
 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.
 5. A posture of defense in fencing, and in bayonet and saber exercise.
 6. An expression or admission intended to secure against objections or censure.
    They have expressed themselves with as few guards and restrictions as I.   --Atterbury.
 7. Watch; heed; care; attention; as, to keep guard.
 8. Zool. The fibrous sheath which covers the phragmacone of the Belemnites.
 Note: ☞ Guard is often used adjectively or in combination; as, guard boat or guardboat; guardroom or guard room; guard duty.
 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.
 ◄ ►