outflow vs valve

outflow

noun
  • A fluid that flows out. 

  • Any outward movement. 

  • Something that flows out of a sewage treatment plant. 

  • The process of flowing out. 

  • A stream of gaseous material emanating from an active galactic nucleus. 

  • The part of a system that allows material to flow out. 

verb
  • To flow outward. 

valve

noun
  • A device that controls the flow of a gas or fluid through a pipe. 

  • One of the pieces or divisions of bivalve or multivalve shells. 

  • One of the pieces into which certain fruits naturally separate when they dehisce. 

  • One of the two similar portions of the shell of a diatom. 

  • A device that admits fuel and air into the cylinder of an internal combustion engine, or one that allows combustion gases to exit. 

  • One or more membranous partitions, flaps, or folds, which permit the passage of the contents of a vessel or cavity in one direction, but stop or control the flow in the opposite direction 

  • A vacuum tube. 

  • A small portion of certain anthers, which opens like a trapdoor to allow the pollen to escape, such as in the barberry. 

  • One of the leaves of a folding-door, or a window-sash. 

verb
  • To control (flow) by means of a valve. 

How often have the words outflow and valve occurred in a corpus of books? (source: Google Ngram Viewer )