Common in 儿媳 ('daughter-in-law') and 媳妇 ('son's wife'). Note the tone of the second syllable: 媳妇 is the son's wife, but toneless 媳妇 in the north often just means 'wife'.
On the right it supplies the sound (shifted to xí) and a faint meaning: 息 can mean 'offspring', so a son's wife is the one who joins to continue the line.
