a horizontal partition above the actual bottom of a box, trunk, etc., especially one forming a secret compartment.
Origin of false bottom
First recorded in 1790–1800
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for false bottom
This is caused by using a false-bottom which is too low or because it is not well perforated.Every Step in Canning|Grace Viall Gray