Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
If material rucks up, it forms a lump (= mass) or folds, and if something rucks it up, it pushes the material into a lump or folds:
Share your knowledge with the community
Browse our collection of 300,000+ community-written definitions
