remap is an option that makes mappings work recursively. By default it is on and I’d recommend you leave it that way. The rest are mapping commands, described below:
:map and :noremap are recursive and non-recursive versions of the various mapping commands. For example, if we run:
:map j gg (moves cursor to first line) :map Q j (moves cursor to first line) :noremap W j (moves cursor down one line)
Then:
jwill be mapped togg.Qwill also be mapped togg, becausejwill be expanded for the recursive mapping.Wwill be mapped toj(and not togg) becausejwill not be expanded for the non-recursive mapping.
Now remember that Vim is a modal editor. It has a normal mode, visual mode and other modes.
For each of these sets of mappings, there is a mapping that works in normal, visual, select and operator modes (:map and :noremap), one that works in normal mode (:nmap and :nnoremap), one in visual mode (:vmap and :vnoremap) and so on.
For more guidance on this, see:
:help :map :help :noremap :help recursive_mapping :help :map-modes