Islamic dowry is “The amount of money or other assets that the husband owes the wife as a result of the marriage..” It is an assertable right of the bride, which may be specified or unspecified and which she may voluntarily waive in whole or in part if she so desires.
However, if the dowry was not specified at the time of marriage or it was not mentioned, then the marriage is still valid, and the dowry remains. That is why dowry is called an ‘inalienable’ right of a wife.
Mahr is sometimes mistranslated as ‘dowry,’ but dowry is what is paid by a woman to a man in some cultures and is not part of Islamic law. Payment of such dowry is an un-Islamic practice that some Muslim cultures have unfortunately adopted from non-Muslim cultures.
The correct translation of Mahr would be “Mahr,” which is an obligation under the Shari’ah in the form of anything of value paid by the groom to the bride at the time of marriage.