What is the difference between MD and MKDIR batch command?

Question

Both command creates folders. I read that MKDIR can create even subfolders.

• Is that only difference?
• Why there are two commands doing the same?
• Which one should I use?

Answer 1

In addition to @npocmaka's answer, I want to provide a list of all such aliases, just for reference:

cd   =  chdir
md   =  mkdir
rd   =  rmdir
ren  =  rename
del  =  erase