ground cloth
noun
: a waterproof sheet placed on the ground for protection (as of a sleeping bag) against soil moisture
Example Sentences
Recent Examples on the Web Additional mulch substitutes include ground cloth, cardboard, newspaper and plastic sheeting. 
Tom Maccubbin, Orlando Sentinel, 3 Sep. 2022 Make sure to grab a ground cloth, which protects the tent floor and keeps out moisture. Lauren Matison, Condé Nast Traveler, 15 Apr. 2021 The plastic ground cloth would end up keeping them out of the mud — at least for the first night of Woodstock. Kirby Adams, The Courier-Journal, 9 Aug. 2019
Tom Maccubbin, Orlando Sentinel, 3 Sep. 2022 Make sure to grab a ground cloth, which protects the tent floor and keeps out moisture. Lauren Matison, Condé Nast Traveler, 15 Apr. 2021 The plastic ground cloth would end up keeping them out of the mud — at least for the first night of Woodstock. Kirby Adams, The Courier-Journal, 9 Aug. 2019 Word History
First Known Use
1931, in the meaning defined above