Definitions
1.nounThe lower surface or part of something."The underneath of the aircraft was painted blue."
2.nounA background radio sound track played during a specific announcement or program.
3.adjectiveUnder, lower."You can have the underneath bunk."
4.adverbBelow; in a place beneath.
5.adverbOn the underside or lower face.
6.prepositionUnder, below, beneath."Underneath the water, all was calm."
7.prepositionUnder the control or power of."There was little freedom underneath the jackboot."