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Related to pion: kaon


Any of the three least massive mesons, having a positive, neutral, or negative electric charge. The charged pions have a mass 273 times that of an electron and a mean lifetime of 2.6 × 10-8 second, and the neutral pion has a mass 264 times that of an electron and a mean lifetime of 8.4 × 10-17 second. Also called pi meson.

[Contraction of pi meson.]


(ˈpaɪɒn) or

pi meson

(General Physics) physics a meson having a positive or negative charge and a rest mass 273.13 times that of the electron, or no charge and a rest mass 264.14 times that of the electron
[C20: from Greek letter pi1 + on]


(ˈpaɪ ɒn)

any of the three lightest mesons, having positive, negative, or neutral electric charge and spin of zero.
[1950–55; pi (meson) + -on1]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.pion - a meson involved in holding the nucleus together; produced as the result of high-energy particle collision
meson, mesotron - an elementary particle responsible for the forces in the atomic nucleus; a hadron with a baryon number of 0
References in classic literature ?
John, and was formerly Christian Church ;) further toward you is the hill of Pion, around whose front is clustered all that remains of the ruins of Ephesus that still stand; divided from it by a narrow valley is the long, rocky, rugged mountain of Coressus.
By-and-by they came to a marvelous cave in the Hill of Pion and entered into it and feasted, and presently they hurried on again.
Paul, where we all did use to go to touch the ancient chains that bound him and be cured of our distempers; I see the tomb of the disciple Luke, and afar off is the church wherein repose the ashes of the holy John, where the Christians of Ephesus go twice a year to gather the dust from the tomb, which is able to make bodies whole again that are corrupted by disease, and cleanse the soul from sin; but see how the wharves encroach upon the sea, and what multitudes of ships are anchored in the bay; see, also, how the city hath stretched abroad, far over the valley behind Pion, and even unto the walls of Ayassalook; and lo, all the hills are white with palaces and ribbed with colonnades of marble.
Sira D' Pion is freely opening her studio to train young girls to always achieve their dreams.
Une peur qui, apres une parade miracle de Bravo sur Ronaldo, prend la forme d'un quatrieme pion humiliant, tant par la solitude du Pistolero que par la passe decisive de Jordi Alba, positionne en numero neuf.
Pion brings more than 25 years of experience in the hotel industry in sales and marketing.
The Fermi discovery builds on a strong hint of neutral pion decay in W44 observed by the Italian Space Agency's AGILE gamma ray observatory and published in late 2011.
The pion is made of a u, d quark-antiquark pair and its mass is about 140MeV.
EVANDER Holyfield failed narrowly to become the oldest heavyweight cham pion of all time as Nikolai Valuev clinched a close majority decision in Switzerland.
The patient had severe dengue haemorrhagic fever and while dengue optic neuropathy remains an unlikely possibility, the authors believe that the case described has features most consistent with PION.
IT was third time lucky for Laura Kenney when the 20-year old Royal Sutton Coldfield runner was crowned Warwickshire Women's Cross Country cham- pion at Hinckley yesterday.
Nugent succeeds Jeffrey Pion, an Executive Vice President in Los Angeles, whose term as a Board member and BOAC Chairman has been completed.