$1,000,000, for short (3)
I believe the answer is:
mil
'$1000000 for short' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mil that I've seen before include "One thousanth of an inch" , "tiny distance" , "One / one thousand inch" , "One thousandth of an inch" .)