What is the difference between a variable and a symbol in LISP?

Question

In terms of scope? Actual implementation in memory? The syntax? For eg, if (let a 1) Is \'a\' a variable or a symbol?

Answer 1

Lisp uses environments which are similar to maps (key -> value) but with extra built-in mechanisms for chaining environments and controlling bindings.

Now, symbols are pretty much, keys (except special form symbols), and point to a value,
ie function, integer, list, etc.
Since Common Lisp gives you a way to alter the values, i.e. with setq, symbols in some contexts
(your example) are also variables.