A blob is a soft, shapeless mass of something, usually thick and somewhat gooey. Picture a glob of jelly that just plopped off your spoon, a dollop of paint squeezed from a tube, or the way melted wax pools into a blob at the base of a candle. The word captures that undefined, rounded quality of something that doesn't hold a firm shape.

In science, biologists sometimes use blob to describe single-celled organisms or masses of cells that don't have a recognizable form. Computer programmers use the term for large chunks of data stored as a single unit, like an image file or video. The word even inspired a classic 1958 sci-fi movie called The Blob, about an alien creature that's exactly what you'd imagine: a growing, formless, gelatinous mass.

The word suggests something squishy and imprecise. When you make a blob of clay before shaping it into something specific, or when you accidentally squeeze out too much toothpaste and it lands in the sink in a blob, you're seeing the word in action. Blob is the perfect word when you need to describe something that definitely exists and has substance, but doesn't have any particular shape worth mentioning.