Definitions of under:

• adjective:   located below or beneath something else

  Example: "The under parts of a machine"

• adverb:   further down

  Example: "See under for further discussion"

• adverb:   down below

  Example: "Get under quickly!"

• adverb:   below the horizon

  Example: "The sun went under"

• adverb:   below some quantity or limit

  Example: "Fifty dollars or under"

• adverb:   in or into a state of subordination or subjugation

  Example: "We must keep our disappointment under"

• adverb:   down to defeat, death, or ruin

  Example: "Their competitors went under"

• adverb:   into unconsciousness

  Example: "This will put the patient under"

• adverb:   through a range downward

  Example: "Children six and under will be admitted free"