Shall I ramble on abit?
It's "code" to codes. Just like it's "sheep" not "sheeps."
Codes
could be used to refer to something like: "Five secret codes needed to be entered into the keypad to unlock the safe!"
A command is not a code, code is made up of commands.
Why be anal about verbage?
Computers are literal, and programmers that are literal know how to write good computer programs.
Example:
You don't call the MBytes on a hard drive memory.
You don't call the MBystes of your RAM storage.
In away they're the same thing. But programmer's who've been around while know right away normally that if you say "storage" you mean some sort of media storage for data such as a hard drive or floppy disk. Programmers know also if you say "memory" you're talking about the computer's RAM not the harddrive.
The more specific your verbage is, the better. The better others will understand what you're trying to say.
And the more likely the computer won't choke on mal-formed syntax or improperly structured code.
At least I might misspell a work in this post and folks would be able to figure out what I was saying, the compiler is not so forgiving.
...end of my rambling!