teaser vs device

teaser and device both are nouns.

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

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

teaser (noun)	device (noun)
a flat at each side of the stage to prevent the audience from seeing into the wings	any clever maneuver
a device for teasing wool	an instrumentality invented for a particular purpose
a particularly baffling problem that is said to have a correct solution	an emblematic design (especially in heraldry)
an advertisement that offers something free in order to arouse customers' interest	any ornamental pattern or design (as in embroidery)
an attention-getting opening presented at the start of a television show	something in an artistic work designed to achieve a particular effect
someone given to teasing (as by mocking or stirring curiosity)
a worker who teases wool