alpha particle alpha orionis • alpha privative · · · Info · Definitions · Characters · · alpha particle · · Text Common · · Latin · · Scripts 14 · · Length 5 · · Syllables Definitions · · · (noun) a positively charged particle that is the nucleus of the helium atom; emitted from natural or radioactive isotopes. Synonyms: alpha particle. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C p latin small letter p U+0070 r latin small letter r U+0072 t latin small letter t U+0074