⌘
From Applepedia
The command key (⌘) is the main function key on the Apple keyboard, serving a similar (though more extensive) purpose as the CTRL key on PC keyboards. Nearly every keyboard shortcut is performed by holding down ⌘ and pressing another key (or holding ⌘ and any combination of option, shift, and/or CTRL and pressing another key).
History
The "clover" symbol has no official name, but is often given nicknames like splat, butterfly, beanie, flower or shamrock. It is identical to the Saint Hannes cross, which is sometimes found in Scandinavia as an ornament on viking artefacts. It is used in Denmark, Norway and Sweden as a symbol of "sites of historical interest", e.g. church ruins. In Sweden, it is used as a roadsign at such places.
The ⌘ came into the Macintosh project at a late stage. The development team originally went for their old apple key, but Steve Jobs found it frustrating when apples filled up the Mac's menus next to the key commands. Since Jobs felt that this was an over-use of the company logo, he opted for a different key symbol. With only a few days left before deadline, the team's bitmap artist Susan Kare started researching for the apple's successor. She was browsing through a symbol dictionary when she came across the cloverleaf-like symbol, used in Sweden for "attractions on a campground". When she showed it to the rest of the team, everyone liked it, and so it became the symbol of the 1984 Macintosh command key.
