subbass

or sub-bass

[ suhb-beys ]
/ ˈsʌbˌbeɪs /

noun Music.

the pedal stop on an organ that produces the deepest or lowest tones; fundamental bass.

British Dictionary definitions for subbass

subbass

subbase

/ (ˈsʌbˌbeɪs) /

noun

another name for bourdon