What do I call my sister in law's sister?

What do I call my sister in law's sister? sister in law Where does the noun sister-in-law come from? The earliest known use of the noun sister-in-law is in the Middle English period OED's earliest sister hood Definition: Sister-in-law refers to the sister of one's spouse or the wife of one's brother It can also refer to the wife of one's spouse's brother

sister hood UK ˈsɪstrɪnlɔːnounWord forms: sisters-in-law1 the sister of one's husband or wife2 the wife of one's sibling or sibling-in-law

ssc4 xwallet link Co-sister-in-law definition: One's husband's brother's wife; or more generally one's spouse's sister-in-law, the sister of one spouse in relation to the sister-in-law published on by Oxford University Press