shift key

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A key on a typewriter that, when depressed, allows uppercase letters and certain symbols to be typed.
• noun A key on a computer keyboard that, when depressed, allows uppercase letters and certain special characters to be typed or changes the function of another concurrently depressed key or button.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The key on a typewriter used to select uppercase letters and certain special characters by physically moving the mechanism
• noun computing A key on a personal computer or terminal keyboard used to effect the same function, or to change the function of the function keys

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the key on the typewriter keyboard that shifts from lower-case letters to upper-case letters