obverse vs picture card

obverse

noun
  • The heads side of a coin, or the side of a medal or badge that has the principal design. 

  • A proposition obtained by obversion, e.g. All men are mortal => No man is immortal. 

adj
  • Corresponding; complementary. 

  • Having the base, or end next to the attachment, narrower than the top. 

  • Turned or facing toward the observer. 

picture card

noun
  • A playing card which has a picture on it (usually Jack, Queen or King (coat card), but sometimes including Ace or Joker). 

  • A trading card/trade card. 

  • A flash memory card for a digital camera. 

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