What is "to be on short commons"

Commons \Com"mons\, n. pl.,

1. The mass of the people, as distinguished from the titled classes or nobility; the commonalty; the common people.

   'T is like the commons, rude unpolished hinds, Could send such message to their sovereign.
   --Shak.

   The word commons in its present ordinary signification comprises all the people who are under the rank of peers.
   --Blackstone.

2. The House of Commons, or lower house of the British Parliament, consisting of representatives elected by the qualified voters of counties, boroughs, and universities.

   It is agreed that the Commons were no part of the great council till some ages after the Conquest.
   --Hume.

3. Provisions; food; fare, -- as that provided at a common table in colleges and universities.

   Their commons, though but coarse, were nothing scant.
   --Dryden.

4. A club or association for boarding at a common table, as in a college, the members sharing the expenses equally; as, to board in commons.

5. A common; public pasture ground.

   To shake his ears, and graze in commons.
   --Shak.

   Doctors' Commons, a place near St. Paul's Churchyard in London where the doctors of civil law used to common together, and where were the ecclesiastical and admiralty courts and offices having jurisdiction of marriage licenses, divorces, registration of wills, etc.

   To be on short commons, to have a small allowance of food.