brother-in-law

Meanings

1. 1
   noun

   A male relative of one's generation, separated by one degree of marriage:

   The US Securities and Exchange Commission has closed its insider trading investigation into stock trades made by then-Sen. Richard Burr and his brother-in-law at the outset of the pandemic, the former senator announced Friday.

2. 2
   noun

   Co-brother-in-law: A male relative of one's generation, separated by two degrees of marriage:

   He was appalled by trench conditions and the prolongation of the war, a disillusionment further encouraged by the Easter rising, in which his brother-in-law, Francis Sheehy-Skeffington (qv), was murdered by a deranged Anglo–Irish officer, J. C. Bowen-Colthurst (qv).

3. 3
   noun

   a brother by marriage

Etymology

From Middle English brother-in-lawe; equivalent to brother + -in-law.