isoelectronicPronunciation: /ˌʌɪsəʊɪlɛkˈtrɒnɪk, -ɛl-/Definition of isoelectronic adjective Chemistry having the same numbers of electrons or the same electronic structure: carbon monoxide is isoelectronic with nitrogenisoelectronic in other Oxford dictionaries Definition of isoelectronic in the US English dictionary