flatten vs plicate

flatten

verb
  • To knock down or lay low. 

  • To reduce (a data structure) to one that has fewer dimensions, e.g. a 2×2 array into a list of four elements. 

  • To press one's body tightly against a surface, such as a wall or floor, especially in order to avoid being seen or harmed. 

  • To make something flat or flatter. 

  • To lower by a semitone. 

  • To combine (separate layers) into a single image. 

  • To be knocked down or laid low. 

  • To become flat or flatter; to plateau. 

  • To make vapid or insipid; to render stale. 

plicate

verb
  • To fold or pleat (usually used in passive). 

adj
  • Folded multiple times lengthwise like a fan, usually lending stiffness to a flat structure such as a leaf; corrugated; pleated. 

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