sister-out-law

Etymology
From, by analogy to.

Noun

 * 1) The sister of one's boyfriend or girlfriend.
 * 2) Girlfriend of one's brother or sister.
 * 3) The sister of one's ex-spouse.
 * 1) The sister of one's ex-spouse.
 * 1) The sister of one's ex-spouse.
 * 1) The sister of one's ex-spouse.
 * 1) The sister of one's ex-spouse.

Coordinate terms

 * sister-in-law