제수

jesu · Younger brother's wife (for a man)

Relationship

my younger brother → his wife

Who uses it

A man, about his younger brother's wife.

When you call them

Call her 제수씨 (jesussi) — 계수씨 is the older variant.

When you talk about them

To others, 제수.

Example

제수씨, 동생이 요즘 많이 바쁘죠?Sister-in-law, my brother's been really busy lately, hasn't he?

Based on the standard etiquette of the National Institute of Korean Language; families and regions vary.