under

1 under /ˈʌndɚ/ preposition
1 under
/ˈʌndɚ/
preposition
Britannica Dictionary definition of UNDER
1 
: in or to a lower place than (something) : below or beneath (something) : underneath
2 
: guided or managed by (a person or group)
3 
: controlled or affected by (something)
4 
: in a particular state or condition : affected by a particular process
5 
: according to (something)
6 
: within the group that has (a particular title or label)
7 
— used to say that a particular name is used to indicate something
8 
: less or lower than (a certain age, amount of money, etc.)
9 
: hidden below (an outward appearance)
2 under /ˈʌndɚ/ adverb
2 under
/ˈʌndɚ/
adverb
Britannica Dictionary definition of UNDER
1 
a  : in or into a position that is below or beneath something
especially : in a position that is below the surface of water
b  : in a forward direction that passes below something
2 
: less than an expected or stated number or amount
3 
: into an unconscious state

go under

— see 1go