Is the wife of one's paternal uncle or maternal uncle a mahram?

Question:
And is the wife of one's paternal uncle a mahram, or not?

Answer:
The wife of one's paternal uncle is not a mahram, nor is the wife of one's maternal uncle, nor the wife of one's brother. So the wife of one's brother, the wife of one's paternal uncle, and the wife of one's maternal uncle are not mahrams. It is not permissible for her to uncover herself before her husband's brother's son, nor before her husband's brother, nor before her husband's sister's son. Rather, she is a non-mahram and must observe the rules of seclusion.
Those who are mahrams are your father's wife, your grandfather's wife; these are mahrams. Your son's wife, your grandson's wife, your daughter's son are mahrams. The wives of fathers and grandfathers are mahrams, and the wives of your sons and your sons' sons are mahrams. As for your brother's wife, no; your paternal uncle's wife, no; your maternal uncle's wife, no.