Something that protrudes, sticks out, or sticks together; a cluster or blob; a mound or mass of no particular shape.
"After she spilled the butter on her hand, it formed an embarrassing lump in her palm."
In plain English: A lump is a small, hard bump that feels different from the smooth skin around it.
"She swallowed the pill with a lump in her throat."
Usage: Use "lump" to describe any irregularly shaped mass or clump without distinct features, such as a pile of snow or a bump on skin. Avoid using it for neatly formed objects like cubes or spheres, which imply specific shapes rather than the amorphous quality this word suggests.
To treat as a single unit; to group together in a casual or chaotic manner (as if forming an ill-defined lump of the items).
"The messy pile of clothes was not sorted but simply lumped into one big heap on the floor."
In plain English: To lump something means to treat it as part of a larger group without making special exceptions for it.
"He lumped all three problems into one big task to finish quickly."
The word lump comes from Middle English lumpe, which traces back to a Germanic root meaning "to glide" or "hang loosely." Over time, the term shifted in usage to describe an irregular mass of matter rather than its original sense of movement.