Noun
A relative who has with the other person only zero parents and three grandparents in common.
A child of maternal half aunt and of paternal uncle at the same time.
A child of paternal half aunt and of maternal uncle at the same time.
A child of maternal aunt and of paternal half-uncle at the same time.
A child of paternal aunt and of maternal half-uncle at the same time.
Source: en.wiktionary.org