axion Syllabification: (ax·i·on)Pronunciation: /ˈaksēˌän/Definition of axion noun Physics a hypothetical subatomic particle postulated to account for the rarity of processes that break charge-parity symmetry. It is very light, electrically neutral, and pseudoscalar. Origin: 1970s: from axial + -onaxion in other Oxford dictionaries Definition of axion in the British & World English dictionary
