cosmic ray cosmic radiation • cosmic string · · · Info · Definitions · Characters · · cosmic ray · · Text Common · · Latin · · Scripts 10 · · Length 4 · · Syllables Definitions · · · (noun) highly penetrating ionizing radiation of extraterrestrial origin; consisting chiefly of protons and alpha particles; collision with atmospheric particles results in rays and particles of many kinds. Synonyms: cosmic ray. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 i latin small letter i U+0069 m latin small letter m U+006D o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 y latin small letter y U+0079