What is "quantum sufficit"

Quantum \Quan"tum\, n.; pl. Quanta. [L., neuter of quantus how great, how much. See Quantity,]

1. Quantity; amount. ``Without authenticating . . . the quantum of the charges.''
   --Burke.

2. (Math.) A definite portion of a manifoldness, limited by a mark or by a boundary.
   --W. K. Clifford.

   Quantum meruit[L., as much as he merited] (Law), a count in an action grounded on a promise that the defendant would pay to the plaintiff for his service as much as he should deserve.

   Quantum sufficit, or Quantum suff. [L., as much suffices] (Med.), a sufficient quantity; -- abbreviated q. s. in pharmacy.

   Quantum valebat[L., as much at it was worth] (Law), a count in an action to recover of the defendant, for goods sold, as much as they were worth.
   --Blackstone.

n. (context medicine English) A sufficient quantity.