unary 
 adjective  Consisting of or involving a single element or component.
 (mathematics) (Of a function) which takes exactly one argument; whose domain has dimension 1.
 (programming) (Of a function, procedure, etc.) which takes exactly one input.


unconditional 
 adjective  absolute, and without conditions, limitations, reservations or qualifications
 We demand your surrender.

undecagon 
 noun (plural undecagons)
 (geometry) A polygon with eleven sides and eleven angles.

uneven 
 adjective
 Not even
 Not level or smooth
 Not uniform
 Varying in quality

uniform 
 noun
 A distinctive outfit as a means of identifying members of a group.
 Phonetic equivalent for the letter U in the ICAO spelling alphabet, informally known as the NATO phonetic alphabet.
adjective
 unvarying, Unvarying; all the same.
 consistent, Consistent; conforming to one standard.

unilateral 
 adjective
 done by one side only
 affecting only one side of the body
 binding or affecting one party only

unit circle 
 noun (plural unit circles)
 (geometry) A circle of radius 1.
 (trigonometry) (the unit circle) The circle of radius 1 with centre at the origin, used in defining trigonometric functions.

Universe 
 proper noun the Universe
 The sum of everything that exists in the cosmos, including time and space itself.
 Powerful telescopes look far back into the distant reaches of the visible universe.

unknown 
 noun
 In algebra, a variable (usually x, y or z) whose value is to be found.
 Any fact or place about which nothing is known. (as in the phrase "into the unknown")
adjective
 Not known; unidentified; not well known.
