Definition of "Under" :

adjective: lower in rank, power, or authority

"An under secretary."

adjective: located below or beneath something else

"The under parts of a machine."

adverb: further down

"See under for further discussion."

adverb: down below

"Get under quickly!."

adverb: below the horizon

"The sun went under."

adverb: below some quantity or limit

"Fifty dollars or under."

adverb: in or into a state of subordination or subjugation

"We must keep our disappointment under."

adverb: down to defeat, death, or ruin

"Their competitors went under."

adverb: into unconsciousness

"This will put the patient under."

adverb: through a range downward

"Children six and under will be admitted free."