IPA: /ˈʌndərˌwɜrld/
KK: /ˈʌndərˌwɜrld/
A place or realm that is thought to be below the earth's surface, often associated with the dead or criminal activities.
In many cultures, the underworld is seen as a place where souls go after death.
Underworld → It is formed from "under" (from Old English "under", meaning beneath or below) and "world" (from Old English "weorold", meaning age or era). The word "underworld" refers to a realm or world that exists beneath the surface of the earth, often associated with the afterlife or a hidden place.
Think of something that exists 'beneath' ('under') the surface of our world ('world') — that's why underworld refers to a hidden realm below.