Nautical. an inward and upward slope of the middle body of a vessel.
Also tum·ble·home. a similar shape for the body of an automobile.
Origin of tumble home
First recorded in 1825–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the inward curvature of the upper parts of the sides of a vessel at or near the stern
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012