Refers to a small, often undesirable lump formed when powder or ground material clumps together, such as flour in batter or ground meat in cooking.
When I added water to the flour, lumps formed.
Mix well so that no lumps form in the pancake batter.
When frying ground meat, cook it while breaking up the clumps.
If you add the egg all at once, the batter tends to become lumpy.
Strain the sauce to remove the lumps before using it.