Definition - What does Command Key mean?
The Command key is a modifier key present on either side of the space bar on a standard Apple keyboard. It is used to perform tasks by pressing it in combination with one or more other keys.
The Command key is also known as the Apple key, clover key, open-Apple key, pretzel key and meta key.
Techopedia explains Command Key
The Command key is used by Apple computers to enter commands in a program or system. Previously the Apple logo was used on the Command key, but was later replaced after Steve Jobs decided that it was an overuse of the symbol. The key is present on the left side of space bar on some compact keyboards, such as on laptops, whereas the keys are present on either side in the common layout. The key performs multiple functionalities when pressed along with other keys. The symbol for the Command key is a looped square, with a Unicode of U+2318.