DECAYとは 意味・読み方・使い方

発音

• (英国発音) IPA: /dɪˈkeɪ/
• 韻: -eɪ
• (米国発音) enPR: dē-kāʹ, IPA: /diˈkeɪ/
• ハイフネーション: de‧cay

名詞

decay (usually uncountable, plural decays)

1. (biology) Rot; any processes or result of organic matter being gradually decomposed, especially by microbial action.

   tooth decay/dental decay—wood-decay fungi—bacterial decay—photochemical decay

   • 1895, H. G. Wells, chapter X, in The Time Machine:

     I fancied at first the stuff was paraffin wax, and smashed the jar accordingly. But the odor of camphor was unmistakable. It struck me as singularly odd, that among the universal decay, this volatile substance had chanced to survive, perhaps through many thousand years.

   • 1914, Robert Frost, The Wood-pile:

     He spent himself, the labour of his axe,
     And leave it there far from a useful fireplace
     To warm the frozen swamp as best it could
     With the slow smokeless burning of decay.

2. Deterioration of condition; loss of status, quality, strength, or fortune.
   • 1841 February–November, Charles Dickens, “Barnaby Rudge. Chapter 10.”, in Master Humphrey’s Clock, volume II, London: Chapman & Hall, […], →OCLC:

     Although the best room of the inn, it had the melancholy aspect of grandeur in decay, and was much too vast for comfort.

   civic and moral decay—systemic decay—fall into decay—urban decay—arrested decay—memory decay

3. (physics) Radioactive decay; decomposition of an atom or its nucleus.

   alpha decay—gamma decay—fission decay—decay chain

   Synonym: nuclear decay—atomic decay

4. (physics) Particle decay; decomposition of a sub-atomic particle.
5. Continuous decrease of a quantity.

   exponential decay—decay rate—orbital decay—decay time—decay constant—time decay

6. (obsolete) Overthrow, destruction, ruin, death.
   • c. 1587–1588 (date written), [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592, →OCLC; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire; London: Scolar Press, 1973, →ISBN, Act II, scene vi:

     Let’s cheere our ſouldiers to incounter him,
     That grieuous image of ingratitude:
     That fiery thirſter after Soueraigntie: […]
     Reſolue my Lords and louing ſouldiers now,
     To ſaue your king and country from decay:

7. (programming) Array decay.

使用する際の注意点

• Historically, definition 1 could not include our modern theories of how such rot occurs. It was something that was restricted to animal and vegetable matter.

派生語

関連する語

動詞

decay (third-person singular simple present decays, present participle decaying, simple past and past participle decayed)

1. (intransitive) To deteriorate, to get worse, to lose strength or health, to decline in quality.

   The pair loved to take pictures in the decaying hospital on forty-third street.

   1. (intransitive, electronics, of storage media or the data on them) To undergo bit rot, that is, gradual degradation.
   2. (intransitive, computing, of software) To undergo software rot, that is, to fail to be updated in a changing environment, so as to eventually become legacy or obsolete.
   3. (intransitive, physics, of a satellite's orbit) To undergo prolonged reduction in altitude (above the orbited body).
      • 2009, Francis Lyall, Paul B. Larsen, Space Law: A Treatise, page 120:

        Damaged on lift-off, Skylab was left in orbit until its orbit decayed.

2. (intransitive, of organic material) To rot, to go bad.

   The cat's body decayed rapidly.

   • 1907, Henry John Elwes and Augustine Henry, The Trees of Great Britain & Ireland, Volume 2/Cladastris:

     The largest tree known to us is at Syon (Plate 124), which in 1904 was no less than 60 feet in height by 7 feet in girth and still a fine tree, though its trunk is decaying inside.

3. (intransitive, transitive, physics, chemistry, of an unstable atom) To change by undergoing fission, by emitting radiation, or by capturing or losing one or more electrons; to undergo radioactive decay.
   • 2005, Encyclopedia of Earth Science, edited by Timothy M. Kusky, →ISBN, page 349:

     Uranium decays to radium through a long series of steps with a cumulative half-life of 4.4 billion years.

4. (intransitive, transitive, physics, of a quantum system) To undergo optical decay, that is, to relax to a less excited state, usually by emitting a photon or phonon.
5. (intransitive, aviation) Loss of airspeed due to drag.
6. (transitive) To cause to rot or deteriorate.

   The extreme humidity decayed the wooden sculptures in the museum's collection in a matter of years.

   • c. 1601–1602 (date written), William Shakespeare, “Twelfe Night, or What You Will”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene v]:

     Infirmity, that decays the wise.

7. (programming, intransitive) Of an array: to lose its type and dimensions and be reduced to a pointer, for example when passed to a function.

同意語

派生語

参照

• “decay”, in OneLook Dictionary Search.
• decay on Wikipedia.Wikipedia
• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “decay”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.

アナグラム

• Dacey