'M3' definitions:

Definition of 'M3'

From: WordNet
noun
A measure of the money supply; M2 plus deposits at institutions that are not banks (such as savings and loan associations)

Definition of 'M3'

From: GCIDE
  • M3 \M3\ n. A broad measure of the money supply, comprising M2 plus deposits at nonbanks such as savings and loan associations. [WordNet 1.5]