under

prep

below; below the surface of; less than; as called for by a law, agreement or system ("The river flows under the bridge." "Such action is not permitted under the law.")

understand

v

to know what is meant; to have knowledge of

unite

v

to join together

universe

n

all of space, including planets and stars

university

n

a place of education that usually includes several colleges and research organizations

unless

conj

except if it happens; on condition that ("I will not go, unless the rain stops.")

until

conj

up to a time; before

up

ad

to, in or at a higher position or value

urge

v

to advise strongly; to make a great effort to get someone to do something

urgent

ad

needing an immediate decision or action

us

pro

the form of the word "we" used after a preposition ("He said he would write to us.") or used as an object of a verb ("They saw us yesterday.")

use

v

to employ for a purpose; to put into action

usual

ad

as is normal or common; as is most often done, seen or heard