Why is a degree-two polynomial called quadratic if quad means four?

[Wannabeagenius]

Hi All,

I have a semantics question.

Why is the quadratic equation called what it is?

A polynomial of degree two is called a quadratic polymonial but I've always associated the root quad to mean four!

Thanks in advance.

Bob

 

[Lamoid]

From wikipedia, "Quadratic equations are called quadratic because quadratus is Latin for "square"; in the leading term the variable is squared."

I always wondered that as well to be honest.

 

[arildno]

Well, what do you call a rectangle whose length is x and breadth is x, and whose area is x^2?

Not a..square?

 

[HallsofIvy]

If you get exercised over this sort of thing (I know I do!), you might find this website to be of interest:
http://pballew.net/etyindex.html

It notes that "quadratic" is from the Latin for "to make square" or, as Lamoid said, simple "square". Of course, a square has four sides which is where your use of the word is from.