Leakage

n. something which escapes or passes through a hole or opening (i.e. liquid, gas, etc.); act of leaking; leak

Leakage describes an unwanted loss, or leak, of something which escapes from its proper location. In everyday usage, leakage is the gradual escape of matter through a leak-hole. In different fields, the term may have specialized meanings.
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Noun
1. the unwanted discharge of a fluid from some container; "they tried to stop the escape of gas from the damaged pipe"; "he had to clean up the leak"
(synonym) escape, leak, outflow
(hypernym) discharge, outpouring, run
(derivation) leak

(n.)
An allowance of a certain rate per cent for the leaking of casks, or waste of liquors by leaking.
  

(n.)
A leaking; also, the quantity that enters or issues by leaking.
  

Release of information to some persons before official public announcement.