A key that, when used with another key, produces an alternative meaning for the other key. Shift, Ctrl, and Alt, are shift keys. You must hold down a shift key for it to take effect. Most people consider the Caps Lock key to be a shift key.
Key on a keyboard that is used to capitalize letters when pressed with that letter key. (Kybdy, Gr. 1)
The shift key works when used in conjunction with another key, giving other keys a second function. For example if you were using a word processing program and press shift and any letter of the alphabet you would type a capital letter. A keyboard normally has two shift keys, one on the left and one on the right and are normally identified by an upward facing arrow.
The key used to produce the uppercase letters on letter keys and the upper character on keys labeled with two characters.
The Shift key (along with the Ctrl key and the Alt key) is a key that modifies the meaning of other keys. If you hold down the Shift key and then briefly type the F1 key, this is a "Shift F1" and it means something different from an F1 key alone. The Shift key is usually used with letters to make upper case letters, but it can alter the meaning of other keys as well.
The shift key is a modifier key on a keyboard, used to type capital letters and other alternate "upper" characters. There are typically two shift keys, on the left and right sides of the row below the home row.