Example sentences
nǚ女ér儿fàng放xué学le了。
My daughter is out of school.
tā他nǚ女ér儿hěn很cōng聪míng明。
His daughter is smart.
About this word
女 is "female" and 儿 is "child", so 女儿 is literally "female child", a daughter. Unlike the 儿 in 哪儿, this one keeps its full reading ér and stays a syllable of its own, which is why pinyin needs the apostrophe: nǚ'ér. The child sense of 儿 also shows in 儿子 (son), 婴儿 (infant) and 儿童 (children), and it pairs 女儿 with 儿子 as the two words a parent uses for their own kids. That parent's-eye view matters. 女儿 is not a general word for a girl; for that, Chinese uses 女孩 or 女生.
The story behind the character
女
A woman kneeling, hands folded in front of her. The standard posture of an ancient Chinese woman. Xu Shen wrote 女, 妇人也. One character, preserving a sitting position from two thousand years ago.
儿
The traditional 兒 is a baby's head with the fontanelle still open (that gap on top) and two legs below. Xu Shen wrote 儿, 孺子也. 孺子 is a little child.