corrugation

During this energetic action the whole fabric is kept in a state of corrugation, and to such extent is rigid.

Small cooking bowl, remarkable for corrugation representing the rising of the boiling waters of a flood.

The floor underfoot was quite different—more of a metallic quality with a curious corrugation.

Only now there were no rocks or bowlders, and the ground was smoother and with a peculiar corrugation.

Then the roof, with a nail in every corrugation, in the concaves instead of the convexes, and the mansion wanted but a floor.