Arithmetical words, Part I

Words, words, words, I'm so sick of words. 
I get words all day through; First from him, now from you!

This refrain from My Fair Lady has stuck in my mind for decades. Of course, as a book editor, I have to look at words all day, if not hear them. And not just any old words, but math words.

Can we consider some of A, Bs and Cs of arithmetic today? These are words anyone who studied arithmetic will have learned (although we may have forgotten a few). I'll try to present these complex words along with clear, brief definitions. But first, how about arithmetic itself:

Arithmetic study of quantities resulting from combining and separating integers, decimals and fractions;

Arithmetic branch of mathematics concerned with calculating numbers using the operations of addition, subtraction, multiplication and division in a defined order

Go ahead, test yourself and see how many you know:

• Acute Angle angle that measures less than 90 degree
• Adjacent Angles angles that are next to each other
• Adjoining Sides sides that meet to form the angles of a figure
• Alternate Exterior Angles outside angles formed when a line intersects two other parallel lines
• Alternate Interior Angles inside angles formed when a line intersects two other parallel lines
• ante meridiem title for time from midnight up to, but not including, noon
• Angle two rays or line segments that intersect or have the same endpoint
• Angle Bisector line or line segment dividing an angle into 2 congruent angles
• Arc continuous section of a circle’s circumference 
• Area the size of an enclosed surface, measured in square units
• Area of a Parallelogram  = base x height; expressed in square units
• Area of a Rectangle area = length x width; expressed in square units
• Area of a Triangle area = 1/2 x (base x height); expressed in square units
• Associative Property: Addition sum stays the same if grouping of addends changes
• Associative Property: Multiplication product stays the same if grouping of factors changes
• Average single number that describes a set of values; could be the mean, median or mode

• Bar Graph chart where bars represent numbers and display data, such as quantities
• Base a polygon’s side or a solid figure’s face; usually the bottom, after which the figure is named
• Bilateral Symmetry a figure that when folded along a line of symmetry forms two halves that are mirror images

• Celsius metric temperature scale with 100 points between freezing and boiling points of water
• Center point in a circle an equal distance from any point on its circumference
• Central Tendency  numerical average; center of a set of values; Mean, median or mode
• Certain an event that will definitely happen; has a probability of 1
• Chord line segment connecting two points on a circle’s circumference 
• Circle closed curve with all points equidistant from a fixed point in the center
• Circular Base a special side of a cone or cylinder that forms a closed curve.
• Circumference the perimeter of a circle
• Closed Figure a figure that begins and ends at one point
• Combination a possible set of events or items
• Commutative Property: Addition  sum remains the same if order of addends changes
• Commutative Property: Multiplication product remains the same if order of factors changes
• Complementary Angles two angles whose sum is 90 degrees
• Composite Number number with more than two factors
• Concave Polygon polygon with four or more sides having at least one internal angle greater than 180°
• Cone 3D figure with 1 vertex, 1 curved edge, 1 circular base and 1 curved surface
• Congruent Figures figures with identical angles and sides of equal lengths; of the same shape and size
• Convex Polygon figure whose internal angles are all less than 180°
• Coordinate Grid area where multiple points may be located by their horizontal and vertical distance from the origin
• Coordinate Point location on a coordinate grid described by 2 numbers (2, -3)
• Cost Per Unit money needed to buy a measured quantity ($1.25 per pound or dozen)
• Cube 3D figure with 8 vertices, 12 congruent straight edges and 6 congruent square flat faces
• Curved Edge curved line segment formed where a curved surface meets a circular base
• Cylinder 3D figure with 2 curved edges, 2 circular bases and 1 curved surface