Definitions by BiochemDude

Sibstitution

The practice of substituting one's friends for their own genetic siblings. May be due to geographic or emotional separation. Sometimes this practice is colloquialized as a brother from another mother BFAM.

Steve's brother couldn't make it to the game, so he made a last minute sibstitution with his friend Mike. Stacy sibstituted her friend Becca, because her sister lived 12 hours away.

Sibstitution by BiochemDude June 14, 2016