conserve vs drain

conserve

noun
  • Wilderness where human development is prohibited. 

  • A jam or thick syrup made from fruit. 

verb
  • To protect an environment, heritage, etc. 

  • To remain unchanged during a process 

  • To save for later use, sometimes by the use of a preservative. 

drain

noun
  • Something consuming resources and providing nothing in return. 

  • One terminal of a field effect transistor (FET). 

  • An access point or conduit for rainwater that drains directly downstream in a (drainage) basin without going through sewers or water treatment in order to prevent or belay floods. 

  • An outhole. 

  • A conduit allowing liquid to flow out of an otherwise contained volume; a plughole (UK) 

  • An act of urination. 

verb
  • To flow gradually. 

  • To draw off by degrees; to cause to flow gradually out or off; hence, to exhaust. 

  • To deplete of energy or resources. 

  • To convert a perennially wet place into a dry one. 

  • To fall off the bottom of the playfield. 

  • To cause liquid to flow out of. 

  • To lose liquid. 

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