power strip vs wall plug

power strip

noun
  • A block of electrical sockets that attaches to the end of a flexible cable and allows multiple electrical devices to be plugged in. 

wall plug

noun
  • An electric socket. 

  • A fixing that allows screws to be fitted into masonry walls, a dowel or screw anchor. 

How often have the words power strip and wall plug occurred in a corpus of books? (source: Google Ngram Viewer )