孙女(sūn nǚ) - granddaughter (paternal family) in Mandarin

孙女 (sūn nǚ) is "granddaughter" specifically on the father's side - a son's daughter. As with 孙子 (sūn zi, "grandson", paternal), Mandarin marks which parent's side a grandchild belongs to; the equivalent through a daughter is 外孙女 (wàisūnnǚ), a different word entirely rather than a variant of this one.

Unlike the neutral-tone 子 (zi) in 孙子 (sūn zi), the 女 (nǚ) in 孙女 (sūn nǚ) keeps its full third tone: say it as sūn nǚ, not sūn nv with a swallowed ending. The character 女 (nǚ) means "female, woman" on its own, and it is the same 女 (nǚ) that opens 女儿 (nǚ'ér, "daughter").

孙女 (sūn nǚ) is used by the grandparents on the father's side, 爷爷 (yéye) and 奶奶 (nǎinai), the same pair who call their grandson 孙子 (sūn zi). A family with both is likely to say 孙子孙女 (sūn zi sūn nǚ) together, "grandsons and granddaughters".