It is said of a marriage between people of different social rank, especially members of the nobility with commoners. In principle it was a limitation, since these unions had to be authorized by some higher entity (such as the king) and the purpose was to prevent the goods and titles of a nobleman from passing into the hands of his spouse. Although the etymology is Latin (morganaticum), it is a late voice taken from the Germanic morgangeba, which was the name for the dowry left by the husband to his wife in case he became a widow.
