The ear speaker (also called the earpiece speaker, ear-piece module) is the small speaker at the top of the phone’s front side that you place near your ear during a call. Its function is to reproduce the caller’s voice so you can hear them when you're talking on the phone.
In this case:
Replacement Earpiece Speaker for Samsung Galaxy Note 8 / N9500 is one example of this component compatible with the Note 8.
It is marketed as a “Ear Speaker Replacement for … Galaxy Note 8” in repair-parts listings.