alpha designator definition, alpha designator meaning | English dictionary

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1    the first letter in the Greek alphabet (Α, α), a vowel transliterated as a  
2      (Brit)   the highest grade or mark, as in an examination  
3    modifier  
a    involving or relating to helium nuclei  
an alpha particle     
b    relating to one of two or more allotropes or crystal structures of a solid  
alpha iron     
c    relating to one of two or more isomeric forms of a chemical compound, esp. one in which a group is attached to the carbon atom to which the principal group is attached  
4    modifier   denoting the dominant person or animal in a group  
the alpha male     
     (via Latin from Greek, of Phoenician origin; related to Hebrew aleph, literally: ox)  

1    foll by the genitive case of a specified constellation   usually the brightest star in a constellation  
Alpha Centauri     
2      (Communications)   a code word for the letter a  
alpha and omega  
1    the first and last, a phrase used in Revelation 1:8 to signify God's eternity  
2    the basic reason or meaning; most important part  
      n   any of a class of drugs that prevent the stimulation of alpha receptors, a type of receptor in the sympathetic nervous system, by adrenaline and that therefore cause widening of blood vessels: used in the treatment of high blood pressure  
Alpha Centauri  
      n   a binary star that is the brightest in the constellation Centaurus and is the second nearest star to the sun. Visual magnitude: 0.0 (A), 1.4 (B); spectral type: G4 (A), K1 (B); distance from earth: 4.3 light years,   (Also called)    Rigil Kent      See also       Proxima  
alpha decay  
      n   the radioactive decay process resulting in emission of alpha particles  
alpha emitter  
      n   a radioactive isotope that emits alpha particles  
      n   a protein that forms in the liver of the human fetus. Excessive quantities in the amniotic fluid and maternal blood may indicate spina bifida in the fetus; low levels may point to Down's syndrome,   (Abbrev.)    afp  
alpha helix  
      n     (Biochem)   a helical conformation of a polypeptide chain, found abundantly in the structure of proteins  
alpha iron  
      n   a magnetic allotrope of iron that is stable below 910°C; ferrite  
alpha particle  
      n   a helium nucleus, containing two neutrons and two protons, emitted during some radioactive transformations  
alpha privative  
      n   (in Greek grammar) the letter alpha (or an- before vowels) used as a negative or privative prefix. It appears in English words derived from Greek, as in atheist, anaesthetic  
alpha radiation  
      n   alpha particles emitted from a radioactive isotope  
alpha ray  
      n   ionizing radiation consisting of a stream of alpha particles  
alpha rhythm   , wave  
      n     (Physiol)   the normal bursts of electrical activity from the cerebral cortex of a drowsy or inactive person, occurring at a frequency of 8 to 12 hertz and detectable with an electroencephalograph  
   See also       brain wave  
alpha stock  
      n   any of the most active securities on the Stock Exchange of which there are between 100 and 200; at least ten market makers must continuously display the prices of an alpha stock and all transactions in them must be published immediately  
1    an in-house test of a new or modified piece of computer software  
      vb   tr  
2    to test (software) in this way  
   Compare       beta-test  
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