What is "paint roller"

n. a roller that has an absorbent surface used for spreading paint

A paint roller is a paint application tool used for painting large flat surfaces rapidly and efficiently.

The paint roller typically consists of two parts: a "roller frame," and a "roller cover." The roller cover absorbs the paint and transfers it to the painted surface, the roller frame attaches to the roller cover. A painter holds the roller by the handle section. The roller frame is reusable. It is possible to clean and reuse a roller cover, but it is also typically disposed of after use.

The roller cover is a cylindrical core with a pile fabric covering secured to the cylindrical core. Foam rubber rollers are also produced. There are both foam and fabric rollers that are individually available (without a handle), made to replace worn out rollers, once an old roller is removed the new roller can be fitted onto the handle section for use. An innovation of the cylindrical core has allowed it to contain paint inside, with the cover absorbing paint from the inside and filtering it through (naturally by wicking) to be applied externally, when the roller is rolled.