What are these "bass" and "treble" that I see in an equalizer ?

I am not an audio person, so do not have much idea about technical terms - but I hear the words “bass” and “treble” almost everywhere now, especially in the equalizer app that came with a new bluetooth earbuds that I bought (yes, I am still very much a wired-earbud guy, just dipping my toes in the wireless earbud ocean)....