poster vs warning sign

poster

noun
  • An advertisement to be posted on a pole, wall etc. to advertise something. 

  • A shot that hits a goalpost, scoring one point. 

  • A shot that hits a goalpost instead of passing into the goal. 

  • A dunk over a defending player. 

  • A picture of a celebrity, an event etc., intended to be attached to a wall. 

  • One who posts a message. 

verb
  • To decorate with posters. 

warning sign

noun
  • A sign that indicates a danger, for example to vehicles on a road or of hazardous chemicals. 

  • An indication that someone or something is in danger or at risk 

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