stemmer vs device

stemmer and device both are nouns.

Word	Noun	Adjective	Verb	Adverb
stemmer	Yes	No	No	No
device	Yes	No	No	No

As nouns, device is a hypernym of stemmer; that is, device is a word with a broader meaning than stemmer:

stemmer (noun)	device (noun)
a device for removing stems from fruit (as from grapes or apples)	any clever maneuver
a miner's tamping bar for ramming packing in over a blasting charge	an instrumentality invented for a particular purpose
an algorithm for removing inflectional and derivational endings in order to reduce word forms to a common stem	an emblematic design (especially in heraldry)
a worker who makes or applies stems for artificial flowers	any ornamental pattern or design (as in embroidery)
a worker who strips the stems from moistened tobacco leaves and binds the leaves together into books	something in an artistic work designed to achieve a particular effect