backslash vs drain

backslash

noun
  • The punctuation mark \. 

  • Used erroneously in reference to, or in reading out, the ordinary slash, that is, the punctuation mark /. 

  • |passage= […] I was trying to find a web-site for which I had been given the following address: http://www.isop.ucla.edu/pacrim/pubs/korjournal.htm. […] I began to work backwards, removing first the last part of the address following the last backslash (/korjournal.htm).}} 

verb
  • To escape (a metacharacter) by prepending a backslash that serves as an escape character, thereby forming an escape sequence. 

drain

noun
  • An act of urination. 

  • 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) 

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 backslash and drain occurred in a corpus of books? (source: Google Ngram Viewer )