Roux-en-Y gastric bypass

noun

ˌrü-ˌen-ˈwī-, ˌrü-ˌän-ˌē-ˈgrek- 

: a gastric bypass surgical procedure in the treatment of severe obesity that involves partitioning off part of the upper stomach (as by stapling and separation from the lower stomach) to form a small pouch, dividing the jejunum into upper and lower parts, and forming a Y-shaped anastomosis by attaching the free end of the lower part of the jejunum to a new outlet on the upper stomach pouch and attaching the free end of what was the upper jejunum to a new opening on the small intestine

called also Roux-en-Y