English word chainsaw comes from English saw, English chain

Detailed word origin of chainsaw

Dictionary entry	Language	Definition
saw	English (eng)	A musical saw.. A sawtooth wave.. A tool with a toothed blade used for cutting hard substances, in particular wood or metal (slang) what's up (either as a greeting or actual question) (intransitive) To be cut with a saw.. (intransitive) To make a motion back and forth similar to cutting something with a saw.. (transitive) To cut (something) with a saw.. (transitive) To form or produce [...]
chain	English (eng)	(computing) To be chained to another data item.. (computing) To relate data items with a chain of pointers.. (figurative) To obligate.. (intransitive) To link multiple items together.. (transitive) To fasten something with a chain.. (transitive) To measure a distance using a 66-foot long chain, as in land surveying.. (transitive) To obstruct the mouth of a river etc with a chain.. [...]
chainsaw	English (eng)	To cut with a chainsaw. A saw that has a power-driven and fast-revolving chain of metal teeth, usually used to cut trees.