# What do you call the part of a plane “in front of or behind” a line segment?

This is a question of terminology.

Suppose we have a line segment AB in a plane. The line segment forms three "zones" in the plane, where the "middle zone" is comprised of points for which some line perpendicular to AB passes through both that point and AB.

Is there a name for this "middle zone"? I want to be able to make a concise statement such as:

Point P is _________ to / in the _________ of the line segment AB.

The reason for my asking is that I'm writing a software function which tests for this quality (I already know how to do this - that's not the question,) and I need to figure out what I should be calling this function in order for its purpose to be clear to other people.

That is, what is the name of the gray zone in this picture:

(Normally web searches answer all my math questions, but it's hard to search what to call something!)

• I've added an image to your post; does it reflect your question? – wchargin Mar 24 '13 at 4:43
• @WChargin Exactly. Thank you! – Kevin Mar 24 '13 at 4:50

I'm not sure if there is a term for this, but the area between two parallel lines is usually called a strip. I'd call this the 'perpendicular strip'.

• That seems to suit well, thanks! – Kevin Mar 25 '13 at 21:14

If you want a mathematical term, I can't help you.

But, as a programmer myself, I understand the need for a memorable, intuitive method name. So, here's the first thing that comes to my mind when I see the pictorial representation: may I suggest the asteroid belt?

(source: spacejockeyreviews.com)

Example method names would be

getAsteroidBeltRadius()
isInAsteroidBelt()


If that's too informal, I suppose belt would suffice. But asteroid belt is much more exciting.

• Interesting idea, although being that it's part of a game development system, depending on the game it's being used for that could become an overload! :) Belt could work but I ended up going with strip, since belt might connote a curved form. – Kevin Mar 25 '13 at 21:12