HotStrings
HotStrings are used to Trigger Commands such as a string replacement.
Hotstrings are mainly used to expand abbreviations as you type them (auto-replace), they can also be used to launch any scripted action. In this respect, they are similar to hotkeys except that they are typically composed of more than one character (that is, a string).
For instance you may have a Hotstring set up so when you type mye it is replaced by your email address.