Now I finally understand a college dining commons!

at Oxford (c1891), a definite portion of victuals supplied from the college buttery or kitchen, at a regular charge…

In wider sense: Rations, allowance of victuals; daily fare.

• 8.049 even after weeks of short commons.

“commons, n.” OED Online. Oxford University Press, June 2016. Web. 28 June 2016.