the act of drilling a hole in the earth in the hope of producing petroleum
"The company began an expensive operation to determine if oil could be found by continuing their drilling efforts deep underground."
Act of drilling.
"The tailor selected a durable drilling fabric to make the sturdy work uniforms."
A long firearm with three barrels (typically a mix of shotgun and rifle barrels).
A heavy, twilled fabric of linen or cotton; drill.
In plain English: Drilling is when you repeat something over and over again until it becomes automatic, often to prepare for an exam or test.
"The drilling for oil in that area has been paused due to bad weather."
Usage: Use this term to refer specifically to the historical multi-barreled firearm known as a "drill gun," not for modern single-shot rifles or military training exercises. It is also used in tailoring contexts to describe a heavy, twilled fabric often called simply "drill."
present participle of drill
"The workers are drilling holes into the wooden beam to secure the shelf."
In plain English: Drilling means making holes by pushing a sharp tool into something hard.
"The construction workers are drilling holes in the wall to install new shelves."
This word comes from combining the verb drill with the suffix -ing. It entered English as a standard way to describe the action of performing drills.