Eighty Shades of Option Key
&gt;Stuck between the Command and Control (ctrl, or ^) keys, the Option key, also called Alt key, because of the switch symbol ... that adorns it<p>No.<p>It&#x27;s called the option key because it was named that on the original 1984 Mac, full stop.  It had one purpose: as an auxiliary shift key, giving access to additional characters and to accents via combos.<p>It&#x27;s never called the &quot;Alt Key&quot;, at least not on MacOS.  IIRC the option key had the word &quot;Alt&quot; above it in the late 1990s primarily to provide some keyboard compatibility with virtual machines etc. that ran Windows 95: in this case, the Option Key served as the IBM PC&#x27;s Alt key.  Later USB Mac keyboards were set up to map Alt and Option to the same keymapping so Mac keyboards could be used on PCs and vice versa.  New Macs no longer include the word &quot;Alt&quot;.<p>What you&#x27;re calling the &quot;switch symbol&quot; didn&#x27;t show up until much, much later.  And the symbol is not called the &quot;switch symbol&quot;.  It&#x27;s called the Option Key Symbol, Unicode U2325.  I doubt it&#x27;s meant to imply &quot;switching&quot; of launching options.<p>It&#x27;s worth mentioning that the NeXT workstation keyboards also had Option keys that worked effectively identically top the Mac.  Late-model Apple IIs had open- and close-apple keys and supposedly the close-apple key served the same function, but I&#x27;m not convinced.<p>&gt; It is (almost) never used alone, but in combination with other keys, to launch various actions.<p>The primary function of the option key has always been as a second shift key.  But just like the shift and control and function keys, the option key can be used as a modifier key for the command key. Various apps have come to use it for their own unusual purposes as well.  This has a long history: even the original MacPaint used the option key in combination with mouse clicks to do alternative things (same thing with the shift key).<p>This notion of multiple shift&#x2F;modifier keys is quite old: the author might look up the concept of the &quot;bucky bit&quot;.<p>The author also seems to have neglected a HUGE use of the option key in Terminal.app: as Emacs&#x27;s META key.