How do expressions like "二嫂" work in Mandarin?
嫂 means &quot;sister-in-law&quot;
杨二嫂  means &quot;wife of the second son of the Yang family&quot;.
It doesn't matter if you are the elder son or third son in the Yang family, she is still 二嫂 (second sister-in-law) to you. The character 二 here doesn't indicate older or younger, it indicates the second born.
Outsiders would call her 杨二嫂 to indicate they are addressing the &quot;Yang's second daughter-in-law.
&quot;second aunt-in-law Yang&quot; is 杨二嬸
&quot;second uncle-in-law Yang&quot; is 杨二叔