A small fragment or piece; especially, a small piece of bread or other food, broken or cut off.
- A very small piece broken from a baked item, such as a cookie, cake, or bread.
- A small fragment, scrap, or portion: eraser crumbs; not a crumb of kindness for you.
- The soft inner portion of bread.
- Slang A contemptible, untrustworthy, or loathsome person.
- To break into very small pieces; crumble.
- To cover or prepare with very small pieces of bread.
- To brush (a table or cloth) clear of small scraps or fragments of food.
- To break apart in very small pieces: a solid cake that won't crumb.