NOUN (1)

1. a measure of the money supply; M1 plus net time deposits (other than large certificates of deposit);

The Collaborative International Dictionary of English v.0.48:

M2 \M2\ n.
   A measure of the money supply broader than M1 but narrower
   than M3, comprising M1 plus net time deposits (other than
   large certificates of deposit).
   [WordNet 1.5]