Is Kite the True Name?

Date: 03/29/2002 at 15:53:00
From: Beecky
Subject: Shape name

I did a kite unit with my class 2 years ago, and I thought at that 
time I found a different "math" name for the KITE shape. I have 
looked in all the books I can find, and searched the Internet hoping 
to find the site that I remembered, as well as asking all the math 
teachers I know, but to no avail. Is KITE the true math name for this 
shape, or is there another? 

Thanks.

Date: 03/29/2002 at 17:01:24
From: Doctor Peterson
Subject: Re: Shape name

Hi, Beecky.

I am not familiar with any other name, though it seems to beg for one, 
since we English speakers don't feel comfortable having plain, easily 
pronounced English names for our geometrical objects! However, 
searching for such a name I found this in Pat Ballew's "Math Words, 
and Some Other Words of Interest":

  http://www.geocities.com/Paris/Rue/1861/arithme5.html#kite   

  In a recent discussion group, John Conway responded to the question
  "Is there a name (other than "kite") for a quadrilateral that looks
  like a kite -- with no parallel sides, but with two pairs of equal
  sides?" His response was to describe a suggestion for a new word, 
  Strombus. Here is the message in Mr Conway's own words.

    I was trying to coin an acceptable word for this for a long time,
    without success until after being prompted by some considerable
    discussion on the net about a year ago, I eventually came up
    with "Strombus", which is derived from the Greek word for a
    spinning top.
    I think it's the best of the terms that were suggested. It's
    interesting that the word "rhombus" is ultimately derived from
    the same source, a fact that lends the new term some
    respectability.
    John Conway 

I also found this note discussing the opposite problem: the fact 
that "kite" is not always defined the same way. (This site uses its 
own non-standard definition!):

   Kites - John C. Pierce
   http://www.math.nmsu.edu/breakingaway/Lessons/kites/kites.html   

   [Note to the reader:

    In this unit we call all quadrilaterals kites. This is not the
    standard definition of a kite. Usually a kite is described as a
    special kind of quadrilateral, but the exact definitions often
    vary. The most general definition that is typically used: A kite
    is a quadrilateral in which one of its diagonals is its axis of
    symmetry. This definition is equivalent to the following one: A
    kite is a quadrilateral that has two pairs of equal adjacent
    sides. These two definitions include rhombuses and non-convex
    quadrilaterals. Other definitions of kites are narrower.
    Sometimes only convex quadrilaterals are called kites and
    non-convex ones are called arrowheads. Sometimes rhombuses are
    excluded by the additional condition that not all sides are of
    equal length.]

All in all, I would continue to use the word kite as defined in Eric 
Weisstein's World of Mathematics (with no alternative name listed):

   Kite
   http://mathworld.wolfram.com/Kite.html   

   A planar convex quadrilateral consisting of two adjacent sides
   of length a and the other two sides of length b. 

But I myself don't usually require kites to be convex, simply because 
we have no other word to describe both convex and non-convex shapes of 
this sort.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/