Son's son's wife
... 孙女婿Son's daughter's husband; Granddaughter's husband 孙媳妇Son's son's wife; Grandson's wife 孙子Son's son; Grandson ...
the eldest granddaughter-in-law
孙媳妇,读音sūn xí fù,汉语词语,意思是孙儿的妻子。出自《儒林外史》第二一回。