M1

 I. (noun) 

Sense 1

Meaning:

A measure of the money supply; includes currency in circulation plus demand deposits or checking account balances

Classified under:

Nouns denoting possession and transfer of possession

Hypernyms ("M1" is a kind of...):

money supply (the total stock of money in the economy; currency held by the public plus money in accounts in banks)

Credits

 Context examples: 

The arteries branching off of the horizontal or M1 segment of the middle cerebral artery in both hemispheres that supply the caudate nucleus and lentiform nucleus.

(Lateral Lenticulostriate Artery, NCI Thesaurus)

As a selective monoaminergic antagonist, olanzapine binds with high affinity binding to the following receptors: serotoninergic, dopaminergic, muscarinic M1-5, histamine H1, and alpha-1-adrenergic receptors; it binds weakly to gamma-aminobutyric acid type A, benzodiazepine, and beta-adrenergic receptors.

(Olanzapine, NCI Thesaurus)