What is the proper name of a push button circuit?

I am doing my first DIY project that includes electricity. I am looking for a push-button switch that breaks the circuit once it is pressed. My goal is to create a closet light that comes on once the door is opened… like a refrigerator. I have searched Home Depot [online], Lowe’s [online], and a myriad of small online shops to find the right name, to no avail. I prefer not to waste gas traipsing around town to find this out.

• What is the proper name of this component?
• Do you know a place online where I can buy this component?
• What brick-and-mortar stores might have it?

Here is an illustration of the component, and the project I want to do:

http://flickr.com/photos/ginatrapani/78927839/in/set-1689472/

Thanks!