marriage with a large income or status gap
Colloquial term, often used when the wife has a significantly higher income or social standing than the husband. Can also refer to the reverse, but the wife-higher pattern is the most common usage.
Apparently, marriages with a big income gap have been increasing lately.
She entered a gap marriage with a man who earns more than double her income.
Compound of 格差 (kakusa, 'gap, disparity') and 婚 (kon, 'marriage'). A modern term reflecting social awareness of economic and status differences in marriage.