Ob

Archaic. Short for "obligation". From Eric Frank Russell's sf classic, "…And Then There Were None" but listed here because fans have used it enough to adopt it as a term of their own. Also a net term.

See also MYOB.

from Fancyclopedia 2

(E F Russell) Obligation. The Gands recognized no debts, only obs to one another (cf Avoidism).