KEEL OVER

v. 1. To turn upside down; tip over; overturn. Usually refers to a boat. The strong wind made the sailboat keel over and the passengers fell into the water. 2. informal To fall over in a faint; taint. It was so hot during the assembly program that two girls who were standing on the stage keeled over. When the principal told the girl her father died, she keeled right over.