harvester vs reaper

harvester and reaper both are nouns.

Word	Noun	Adjective	Verb	Adverb
harvester	Yes	No	No	No
reaper	Yes	No	No	No

As nouns, harvester and reaper are synonyms defined as:

harvester and reaper: farm machine that gathers a food crop from the fields

As nouns, harvester and reaper are synonyms defined as:

harvester (noun)	reaper (noun)
farm machine that gathers a food crop from the fields	farm machine that gathers a food crop from the fields
someone who helps to gather the harvest	someone who helps to gather the harvest