standard

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

• adjective Serving as or conforming to an established or accepted measurement or value.
• adjective Widely recognized or employed as a model of authority or excellence.
• adjective Acceptable but of less than top quality.
• adjective Normal, familiar, or usual.
• adjective Commonly used or supplied.
• adjective Linguistics Conforming to models or norms of usage admired by educated speakers and writers.
• noun An acknowledged measure of comparison for quantitative or qualitative value; a criterion. synonym: ideal.
• noun An object that under specified conditions defines, represents, or records the magnitude of a unit.
• noun The commodity or commodities used to back a monetary system.
• noun The set proportion by weight of gold or silver to alloy metal prescribed for use in coinage.
• noun A degree or level of requirement, excellence, or attainment.
• noun Something, such as a practice or a product, that is widely recognized or employed, especially because of its excellence.
• noun A set of specifications that are adopted within an industry to allow compatibility between products.
• noun A requirement of moral conduct.
• noun A flag, banner, or ensign, especially.
• noun The ensign of a chief of state, nation, or city.
• noun A long, tapering flag bearing heraldic devices distinctive of a person or corporation.
• noun An emblem or flag of an army, raised on a pole to indicate the rallying point in battle.
• noun The colors of a mounted or motorized military unit.
• noun Chiefly British A grade level in elementary schools.
• noun A pedestal, stand, or base.
• noun The large upper petal of the flower of a pea or related plant.
• noun One of the narrow upright petals of an iris.
• noun A shrub or small tree that through grafting or training has a single stem of limited height with a crown of leaves and flowers at its apex.
• noun Music A composition that is continually used in repertoires.

from The Century Dictionary.

• noun A weight, measure, or instrument by comparison with which the accuracy of others is determined; especially, an original standard or prototype, one the weight or measure of which is the definition of a unit of weight or measure, so that all standards of the same denomination are copies of it. The only original standard of the United States is a troy pound. See pound, yard, meter.
• noun In coinage, the proportion of weight of fine metal and alloy established by authority.
• noun That which is set up as a unit of reference; a form, type, example, instance, or combination of conditions accepted as correct and perfect, and hence as a basis of comparison; a criterion established by custom, public opinion, or general consent; a model.
• noun A grade; a rank; specifically, in British elementary schools, one of the grades or degrees of attainment according to which the pupils are classified.
• Serving as a standard or authority; regarded as a type or model; hence, of the highest order; of great worth or excellence.
• noun An upright; a small post or pillar; an upright stem constituting the support or the main part of a utensil.
• noun In carpentry, any upright in a framing, as the quarters of partitions, or the frame of a door.
• noun In ship-building, an inverted knee placed on the deck instead of beneath it.
• noun That part of a plow to which the mold-board is attached.
• noun In a vehicle: A support for the hammer-cloth, or a support for the footman's board. See cut under coach.
• noun An upright rising from the end of the bolster to hold the body laterally.
• noun In horticulture: A tree or shrub which stands alone, without being attached to any wall or support, as distinguished from an espalier or a cordon.
• noun A shrub, as a rose, grafted on an upright stem, or trained to a single stem in tree form.
• noun A stand or frame; a horse.
• noun A large chest, generally used for carrying plate, jewels, and articles of value, but sometimes for linen.
• noun A standing cup; a large drinking-cup.
• noun The chief dish at a meal.
• noun A suit; a set. Compare stand, n., 11.
• noun One who stands or continues in a place; one who is in permanent residence, membership, or service.
• Standing; upright; specifically, in horticulture, standing alone; not trained upon a wall or other support: as, standard roses.
• noun In horticulture, a fruit-tree that grows to its normal size, that is, is not dwarfed; in Great Britain, a tree or other plant that is grown to a single trunk, in distinction from one that is grown in bush form.
• noun In forestry, a tree from 1 to 2 feet in diameter, breast-high.