These are our Math Dictionary words that start with U words.
Ok. There are not very many terms in this list.
U.S. Customary System - a system of measurement used almost exclusively in the United States of America. (teaspoon, tablespoon, ounce, cup, pint, quart, gallon; inch, foot, yard, mile; ounce, pound, ton)
Undefined - if the denominator of a fraction is 0, then the fraction is undefined.
Undefined Slope - vertical lines that have slopes that are called undefined.
Unilateral Surface - a surface with only one side, such as a Moebius strip.
Unimodal - a finite sequence is unimodal if it first increases and then decreases.
Unimodular - a square matrix is unimodular if its determinant is 1.
Union of Sets - the set of all the objects contained by at least one of the sets. The symbol for union is U.
Unit - a single thing used as a standard or measure.
Unit Circle - a unit circle is a circle with radius 1, circle of radius 1 centered at the origin (0,0) of the Cartesian coordinate system.
Unit Cube - a cube with edge length 1.
Unit Fraction - a fraction whose numerator is 1.
Unit Square - a unit square is a square of side length 1.
Unitary Divisor - a divisor d of c is called unitary if gcd(d,c/d) = 1.
Units column - the first column of numbers to the left of the decimal point.
Unity - one
I keep these definitions as a glossary in my binder.