What do the brackets mean in x86 asm?

Question

Given the following code:

L1     db    \"word\", 0

       mov   al, [L1]
       mov   eax, L1

What do the brackets ([L1]) represent?

Answer 1

[L1] means the memory contents at address L1. After running mov al, [L1] here, The al register will receive the byte at address L1 (the letter 'w').