A saw that has a power-driven and fast-revolving chain of metal teeth, usually used to cut trees.
"He grabbed the chainsaw from the shed to quickly clear down the old oak tree blocking our driveway."
To cut with a chainsaw.
"The logger used his chainsaw to fell the massive oak tree blocking the path."
The word chainsaw is a compound of the words chain and saw. It refers to the tool's cutting mechanism, which uses a continuous loop of teeth rather than a single blade.