The audio frequencies between about 20Hz and 250Hz. New music with synthesized effects can be produce very powerful low notes, so reproduction in the 30 to 50hz region becomes important.

A low-frequency sound or instrument which is used to enhance music or provide some sort of musical ground. Most modern music uses electronically-generated bass synths, while traditionally-created music uses low-frequency instruments for the bass.

Bass can also be referred to an audio setting that makes the low frequencies of a song more pronounced.

BASS in the colloquial description used in situations where someone is so overweight the fat on their BACK hangs down and merges with their ASS with no obvious demarcation between the two (i.e. their Back combines with their Ass to form a new single body part - their BASS).

Also refer to GUNT (i.e. a merged Gut and Cunt) and GENIS (i.e. a merged Gut and Penis).

This word has multiple meanings. I see that the musical instrument part and fish part are well written already, so I'll skip these two and define it according to Meghan Trainor's songs:
Bass, in contrary to treble, refers to women that are not model-thin, and has confident in their body shape; they don't try to lose weight unhealthily, or feel sorry for themselves for not being 'fit' to society's trending standards.

He is the very gay, he fucks horses everyday. He does not have a life. Basse is a bad person with a tiny penis.

The part of your body between your BALLS and your ASS. Derived by combining Balls + Ass = Bass. A.K.A. "Gooch", "Chode".

adds to the sound of a guitar, while a guitar makes a bass sound not-boring.