Definition of "waffled"

The US "pineapple" grenade's iron outer surface was waffled to aid its fragmentation into jagged shrapnel when it exploded.

2001, Randy Holderfield, Michael J. Varhola, D-Day: The Invasion of Normandy, June 6, 1944, page 73

In a light white dress that I think was waffled cotton, or possibly a very light pastel blue. The color occurs to me when I look at the photo, unembodied, floating alongside of it. It's in black and white. Probably snapped before color […]

2001, Rela Mazali, Maps of Women's Goings and Stayings, page 213

Nate and Amy were waiting in the lobby of the Maui county jail in Wailuku, sitting in metal chairs designed to promote discomfort and waffled butt skin.

2004, Christopher Moore, Fluke: Or, I Know Why the Winged Whale Sings, HarperCollins, page 85

You have seen catering trucks: shiny stainless steel that is waffled with creases that look like diamonds.

2007, Paul Ferrara, Flash of Eden, AuthorHouse, page 38

The primary barrier between the cargo and the first layer of insulation, and the secondary barrier between the two layers of insulation, were waffled or corrugated stainless steel plates free to contract or expand independently […]

1996, Michael D. Tusiani, The Petroleum Shipping Industry: A nontechnical overview