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null

null / nəl/ • adj. 1. having no legal or binding force; invalid: the establishment of a new interim government was declared null and void. 2. having or associated with the value zero. ∎  Math. (of a set or matrix) having no elements, or only zeros as elements. ∎  lacking distinctive qualities; having no positive substance or content: his curiously null life. • n. poetic/lit. a zero. ∎  a dummy letter in a cipher. ∎  Electr. a condition of no signal. ∎  a direction in which no electromagnetic radiation is detected or emitted. • v. [tr.] Electr. combine (a signal) with another in order to create a null; cancel out.

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null

null not valid (n. and void) XVI; insignificant; non-existent XVIII. — (O)F. nul, fem. nulle, or L. nūllus, -a no, none, f. ne (see NO3) + ūllus any, f. ūnus ONE.
So nullify make null XVI. — late L. nullificāre despise. nullification XVIII. nullity XVI. — F. or medL.

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null

null null and void having no legal or binding force.
null hypothesis in a statistical test, the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

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Null

NULL

Of no legal validity, force, or effect; nothing. As used in the phrase null and void, refers to something that binds no one or is incapable of giving rise to any rights or duties under any circumstances.

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2,4-D

: see herbicide.

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null

nullannul, cull, dull, gull, hull, lull, mull, null, scull, skull, Solihull, trull, Tull •seagull • multihull • monohull •numbskull • Elul

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2,4-D

2,4-D 2,4-dichlorophenoxyacetic acid (herbicide)

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2,4-D

2,4-D (2,4-dichlorophenoxyacetic acid) See AUXIN.

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2,4-D

2,4-D 2,4-dichlorophenoxyacetic acid (2,4-dichlorophenoxyethanoic acid): a synthetic auxin used as a weedkiller of broad-leaved weeds. See also pesticide.

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2,4-D

2,4-D

One of the nation's most popular weed killers, the herbicide 2,4-D (also known as 2,4-dichlorophenoxyacetic acid ) has been widely used by homeowners, timber companies, government agencies, farmers, and power companies to eliminate unwanted vegetation from lawns, golf courses , forests, rangelands , rights-of-way, pastures, highways, and even farmlands. Scientists and environmentalists have warned for years of the chemical's toxic effects, and Rachel Carson's classic book Silent Spring described its dangers to human health and the environment . Subsequent studies have linked 2,4-D to cancers, miscarriages, and birth defects in animals and humans who have been exposed to it. Agent Orange , a defoliant used during the Vietnam War, was a 50/50 mixture of 2,4-D and a similar herbicide, 2,4,5-T . For years environmentalists have urged that 2,4-D be banned or strictly controlled, but the U.S. Environmental Protection Agency (EPA) has so far not acted to do so.

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