puzzle vs riddle

puzzle

noun
  • The state of being puzzled; perplexity. 

  • Anything that is difficult to understand or make sense of. 

  • A riddle. 

  • A game for one or more people that is more or less difficult to work out or complete. 

  • A jigsaw puzzle. 

  • A crossword puzzle. 

verb
  • To think long and carefully, in bewilderment. 

  • To perplex, confuse, or mystify; to cause (someone) to be faced with a mystery, without answers or an explanation. 

  • To make intricate; to entangle. 

riddle

noun
  • A verbal puzzle, mystery, or other problem of an intellectual nature. 

  • A board with a row of pins, set zigzag, between which wire is drawn to straighten it. 

  • A sieve with coarse meshes, usually of wire, for separating coarser materials from finer, as chaff from grain, cinders from ashes, or gravel from sand. 

  • An ancient verbal, poetic, or literary form, in which, rather than a rhyme scheme, there are parallel opposing expressions with a hidden meaning. 

  • One of the pair of curtains enclosing an altar on the north and south. 

verb
  • To fill with holes like a riddle. 

  • To speak ambiguously or enigmatically. 

  • To fill or spread throughout; to pervade. 

  • To put something through a riddle or sieve; to sieve; to sift. 

  • To solve, answer, or explicate a riddle or question. 

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