Annihilation radiation
electromagnetic radiation produced by the coalescence and mutual annihilation of a positron and an electron, each pair forming two photons having a minimum energy of 0.5 million electron volts each.
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- Anniv.
. anniversary
- Anniversary reaction
a psychological reaction, as depression, occurring at a regularly fixed time and -ssociated with the recollection of an emotionally upsetting past experience, as loss of a loved one.
- Anniversary day
noun (nz) a day for celebrating the foundation date of one of the former provinces
- Anno aetatis suae
in the year of his age; in the year of her age.
- Anno domini
. historical examples every one knows that there is nothing so untruthful as anno domini, and im convinced that neither of us is a day more than thirty. the bishop’s apr-n w. somerset maugham anno domini 1619, he was ten yeares old, as by his picture; and was then a poet. brief lives (vol. 2 […]