balance

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A weighing device, especially one consisting of a rigid beam horizontally suspended by a low-friction support at its center, with identical weighing pans hung at either end, one of which holds an unknown weight while the effective weight in the other is increased by known amounts until the beam is level and motionless.
• noun A state of equilibrium or parity characterized by cancellation of all forces by equal opposing forces.
• noun The power or means to decide.
• noun A state of bodily equilibrium.
• noun The ability to maintain bodily equilibrium.
• noun A harmonious or satisfying arrangement or proportion of parts or elements, as in a design.
• noun An influence or force tending to produce equilibrium; counterpoise.
• noun The difference in magnitude between opposing forces or influences.
• noun Equality of totals in the debit and credit sides of an account.
• noun The difference between such totals, either on the credit or the debit side.
• noun Something that is left over; a remainder.
• noun Chemistry Equality of mass and net electric charge of reacting species on each side of an equation.
• noun Mathematics Equality with respect to the net number of reduced symbolic quantities on each side of an equation.
• noun A balance wheel.
• intransitive verb To determine the weight of (something) in a weighing device.
• intransitive verb To consider and compare or assess.
• intransitive verb To bring into or maintain in a state of equilibrium.
• intransitive verb To act as an equalizing weight or force to; counterbalance.
• intransitive verb To compute the difference between the debits and credits of (an account).
• intransitive verb To reconcile or equalize the sums of the debits and credits of (an account).
• intransitive verb To settle (an account, for example) by paying what is owed.
• intransitive verb To bring into or keep in equal or satisfying proportion or harmony.
• intransitive verb Mathematics & Chemistry To bring (an equation) into balance.
• intransitive verb To move toward and then away from (a dance partner).
• intransitive verb To be in or come into equilibrium.
• intransitive verb To be equal or equivalent.
• intransitive verb To sway or waver as if losing or regaining equilibrium.
• intransitive verb To move toward and then away from a dance partner.
• idiom (in the balance) In an undetermined and often critical position.
• idiom (on balance) Taking everything into consideration; all in all.

from The Century Dictionary.

• noun In engines, a condition in which the forces at play due to the masses of the moving mechanism are balanced by others which operate in a contrary sense, so that the engine has no tendency to lift or slide upon its foundation, but would run without jar even if not secured to such foundation.
• noun An instrument for determining the weight of bodies as compared with an assumed unit-mass.
• noun Any apparatus for weighing, as a steelyard or a spring-balance.
• noun One of the scales of a balance; in the plural, scales.
• noun The act of weighing mentally; the act of comparing or estimating two things as in a balance.
• noun An equivalent or equalizing weight; that which is put into one scale to offset the weight in the other; the weight necessary to make up the difference between two unequal weights; a counterpoise, literally or figuratively. Specifically
• noun In mining, a counterpoise or counterweight used in such a way as to assist the engine in lifting the load.
• noun The part of a clock or watch which regulates the beats: formerly, a pin oscillating on its center, and thus resembling the beam of a balance; now, a wheel. See balance-wheel.
• noun The arithmetical difference between the two sides of an account: as, to strike a balance.
• noun The sum or amount necessary to balance the two sides of an account, usually spoken of as a debit or a credit balance: as, I have still a balance at my banker's; a balance still due.
• noun A surplus; a remainder; the rest; the residue; what remains or is left over: as, he bequeathed the balance of his estate to A. B.; the balance of a meal.
• noun A balanced condition; a state of equilibrium or equipoise: as, to lose one's balance.
• noun Harmonious arrangement or adjustment; just proportion, especially in the arts of design.
• noun In astronomy, a sign of the zodiac, called in Latin Libra, which the sun enters at the equinox in September.
• noun a weighing apparatus somewhat resembling the steelyard, but differing from it in having the fulcrum movable, the weight being at one end and the load at the other; the loop by which it is suspended is shifted along the beam until equilibrium is established. The weight of the substance in the scale-pan is indicated by the point at which the fulcrum is placed when the instrument is in equilibrium.
• To weigh; especially, to weigh or consider in the mind; ponder over.
• To estimate the relative weight or importance of, as two or more things; make a comparison between as to relative importance, force, value, etc.