Definition of the word plug away

The phrase "plug away" is a figurative expression that originated in the mid-19th century in the United States. Its literal meaning is to insert a plug into a hole to block it or seal it. However, by the late 1800s, the term had taken on a figurative meaning to describe persistent and continuous effort towards achieving a goal. The origin of this expression can be traced back to the Industrial Revolution when coal mines were being opened up at a rapid pace. Miners used wooden or clay plugs to seal off narrow passages or fissures in the coal seams to prevent the escape of coal dust and gas, which was a major health hazard. The plugs were also used to prevent groundwater from flooding the mines. The term "plug away" was coined as a result of the vigorous efforts of the miners who would meticulously plug away at their work, sometimes for long hours, using these plugs. The phrase quickly spread beyond the mining industry to other professions and became widely used in everyday English to describe hard, consistent work towards achieving a goal.