noun

• (uncountable, collective) Items that have been or are about to be ejected from a boat or balloon.
• (countable) The action of jettisoning items.

verb

• (figurative) To let go or get rid of as being useless or defective.
  "Among the most modern of all the Pacific stock in Great Britain is the stud of "Merchant Navy" and "West Country" Pacifics on the Southern Region, and the rebuilding which is now being carried out, preserving all the best features of the Bulleid designs—such as the free-steaming boiler—and jettisoning the features that have given trouble, in particular the chain-driven valve-motion, should give the Southern a supply of highly-competent machines able to last out the remaining life of steam on the S.R."